Tire inspection system

ABSTRACT

An automated tire inspection system employs penetrative emanation such as X-radiation to inspect the integrity of portions of tires fed sequentially along a feed path through a centering station and into a shielded enclosure which where an inspection station is defined. Features of the system include: (1) the use of a pressure regulator to control the force applied by spindles to the beads of a tire to support the tire for inspection; (2) the structures of several components including carriages, sub-carriages, and sub-sub-carriages for movably supporting an X-ray source and an X-ray imaging system, a pair of spindle support carriages which movably carry two sets of spindles, and a centering table and a main conveyor for feeding tires to the inspection station.

REFERENCE TO RELATED AND RELEVANT PATENTS AND APPLICATIONS:

TIRE INSPECTION APPARATUS, Ser. No. 95,859 filed Dec. 7, 1970 by AnthonyPalermo, Jr., issued Mar. 25, 1975 as U.S. Pat. No. 3,873,837, here the"Tire Inspector Patent", the disclosure of which is incorporated byreference.

METHOD AND APPARATUS FOR INSPECTING TIRES, Ser. No. 254,939 filed May19, 1972 by Richard L. T. Fox, issued Oct. 22, 1974 as U.S. Pat. No.3,843,888, here the "Tire Handling Patent".

TIRE INSPECTION SYSTEM, Ser. No. 495,379 filed Aug. 7, 1974 by Donald N.Heisner, here the "Systems Patent".

TIRE INSPECTION SYSTEM, Ser. No. 495,448 filed Aug. 7, 1974 by Donald N.Heisner and Phillip K. Loyer, here the "Operations Patent".

TIRE INSPECTION SYSTEM, Ser. No. 495,447 filed Aug. 7, 1974 by Donald N.Heisner, Anthony J. Palermo and Phillip K. Loyer, here the "ShieldedStructures Patent".

TIRE INSPECTION SYSTEM, Ser. No. 495,377 filed Aug. 7, 1974 by Donald N.Heisner and Charles R. Bentivegna, here the "Controls Patent".

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a tire inspection system includingapparatus and methods for inspecting the integrity of tires through theuse of penetrative emanation, such as X-radiation.

2. Background Terminology

Several terms of art are commonly used in conjunction with tires. Theouter diameter or O.D. of a tire is measured to an outer wear surfaceknown as the tire "tread", even though it may be a smooth surface. Theannular sides of a tire are called sidewalls. The inner diameter or I.D.of a tire is measured to sidewall portions called beads. The axis aboutwhich a tire is intended to rotate, i.e., the axis common to both tirebeads, is called the central axis. A plane which extends perpendicularto the central axis and intersects the center of the tire tread iscalled the central plane. The open space inside a tire and radiallyoutwardly of the beads is called the tire torus. The open space inside atire which includes the torus and the space radially inwardly of thebeads is called the tire annulus. The distance from the outer surface ofone sidewall to the outer surface of the other sidewall is called thewidth of the tire.

3. Prior Art

A number of proposals have been made for inspecting tires with X-raysand other penetrative emanation. Inspection with X-radiation hasadvantages over other known tire inspection methods, in that it providesinformation about the internal structure or integrity of a tireincluding a clear indication of whether internal components such assteel belts and the like are properly positioned and intact.

In the past, X-ray tire inspectors were used primarily as laboratorytools. Little use was made of X-ray inspection equipment on high rateproduction lines for a number of reasons including:

1. The inspection system was a relatively expensive piece of apparatus;

2. The apparatus could only inspect a limited number of tires from aproduction run due to its relatively slow operation;

3. A significant amount of tire handling and manipulation was typicallyrequired to position a tire in the apparatus for inspection; and,

4. After a tire was positioned for inspection, the apparatus was notcapable of inspecting the total tire from bead to bead, withoutrequiring that the tire be repositioned one or more times for successiveinspection runs.

In view of these disadvantages, X-ray inspection of production tires wastypically used either to inspect only selected portions of tiresrandomly sampled from a production run, or to inspect special duty tiressuch as are used on aircraft and on heavy duty, off-highway roadequipment.

With the recent increased emphasis on vehicle safety, and the advent ofsteel belted tires, the need for X-ray inspection of all tires from aproduction run has become apparent. A number of proposals have been madeto improve X-ray inspection apparatus, providing a capability to handlea large volume of tires of the same size from a production run.

A significant advance was made in tire inspection capability with theintroduction of a rotatable X-ray tube, as described in the referencedTire Inspector Patent. The rotatable tube permitted the completeinspection of a tire from bead to bead without requiring anyreorientation of the tire or tube. With the tube located at a singleposition within or near the tire beads and with the tire rotating aboutits central axis, the tube is positioned to inspect one tire bead and isthen scanned through a full arc inspecting tread, sidewalls and theother tire bead.

Still another advance was made with the introduction of a tire inspectorhaving multiple-function tire supporting spindles, as described in thereferenced Tire Handling Patent. Two sets of spindles carried onseparate carriages are inserted into the annulus of a tire to beinspected. The sets of spindles enter the tire axially from oppositesides. Once the spindles have entered the annulus, they move indirections parallel to the central plane to engage the tire beads. Whilethe spindles continue to engage the tire beads, they are operable tosupport beads of the tire axially away from each other as may berequired to facilitate inspection. The use of multi-function spindleshas greatly simplified the manipulation of tires for inspection.

Despite the fact that several advances have been made in X-ray tireinspection, little has been done to satisfy the need for an X-ray tireinspector which is capable of efficiently, automatically and safelyinspecting tires of a wide range of admixed sizes. Prior art inspectionapparatus has not been well adapted to sequentially inspect tires ofmixed sizes, and accordingly has not met the needs of a number of tiremanufacturers whose production includes an admixture of tire sizes.

A recent proposal has suggested the use of a tire size sensing systemfor measuring tire O.D. and width before a tire is admitted to anenclosure for X-ray inspection. Once the measured tire has entered theenclosure which surrounds the X-ray inspection system, the tire tread isengaged by rotatable spools and is elevated to position its centralplane in alignment with the center of the screen of an X-ray imagingsystem. An X-ray tube is then swung upwardly into the tire annulus andturned onto initiate the inspection. Inspection continues as the tire isrotated by the spools. The X-ray tube and the imaging system aremachanically coupled together so that both can be pivoted upwardly anddownwardly to inspect the tire sidewalls.

This recent proposal has a number of disadvantages. Positioning of thetire for inspection continues to require a substantial amount ofstep-by-step tire manipulation. The tire is first engaged by spools. Thetire is then elevated by the spools to an inspection level.Beadspreaders are then inserted into one side of the tire torus andextended to spread the tire bead. Each of these steps must be performedin sequence, it being necessary for the tire to be raised into positionbefore the beads can be spread. When these steps are completed, theX-ray tube is then swung into position from below.

Another disadvantage with this recent proposal is that X-ray tubeoperation must be terminated between tire inspections. Repeatedlyenergizing and de-energizing the tube and its associated generatorequipment may add to the required inspection time and may also diminishthe operating life of the X-ray tube.

Another disadvantage of previously proposed X-ray tire inspectionapparatuses is their inflexibility of operation. While computers havebeen used to some extent to facilitate and speed up the operation of theapparatus, no use has been made of a programmable computer system topermit inspection cycles to be widely varied by altering the program,without the need for mechanical changes in the apparatus.

Still another disadvantage of prior proposed inspection apparatuses isthat their several movable components are not independently operable anddo not utilize servo-system technology to permit their operation to becontrolled and monitored from a central control console. No thoroughsystem of malfunction analysis has been provided on known tireinspectors.

The use which is made of computer systems in prior proposals includesthe storage of sensed tire size data, and the subsequent control of theapparatus to inspect a tire of the sensed size. The computer is operatedin an open loop fashion. Command signals are issued by the computer tocomponents of the apparatus. If the components respond as intended, aproper inspection sequence is carried out.

The open loop mode of operation has several disadvantages. While thecomputer issues commands, it has no knowledge of whether the commandsare properly executed. The computer cannot sense the conditions andpositions of the components it commands and this makes it difficult toprevent the occurrence of potentially destructive or dangerousconditions. If the computer issues a defective command or if theapparatus improperly executed a command, potentially destructive ordangerous conditions can easily arise.

Still another disadvantage of open loop operation is that no use can bemade of the computer to assist in analyzing a malfunction. When a defectarises, it is often difficult to diagnose, and substantial machine downtime may result before the malfunction is analyzed and corrected.

Still another drawback of the proposed use of open loop computer controlsystems in tire inspectors is the failure of such systems to provide forhuman intervention in the inspection procedure. The operator cannotinterrupt the procedure to change its sequence, or to skip certainsteps, or to add certain steps, or to lengthen or shorten certain steps.The versatility of these proposed systems leaves much to be desired.

SUMMARY OF THE INVENTION

The present invention overcomes certain of the foregoing and otherdrawbacks of the prior art and provides a novel and improved tireinspection system. The invention includes both method and apparatusfeatures.

A significant advantage of appartus constructed in accordance with theinvention is its ability to adjust rapidly and automatically to the sizeof each tire fed to the machine for inspection. This capability enablesthe apparatus to inspect tires of a wide variety of sizes as they emergefrom their respective production lines. Tires having an inner diameteras small as 10 inches can be accommodated at one end of the range. Tireshaving an outer diameter of 56 inches and weighing as much as about 750pounds can be accommodated at the other end of the range. Moreover, theapparatus can accommodate tires one after the other which are atopposite extremes of this size range.

No manual adjustments to the apparatus or manual control of theinspection process are required unless the operator so desires. All theoperator need do is to attend a control console to watch for tire flawsto appear on his TV monitor, and to monitor the operation of theapparatus in case some malfunction should be indicated on his controlconsole. If the operator desires to interrupt the programmed sequence ofoperation, he may do so at any time to eliminate, add, shorten orlengthen steps.

The tire inspector is designed to be positioned between two conventionaldriven conveyor sections. Tires are fed one at a time from one of theconveyor sections onto a centering table. The centering table retainsthe tire for admission to a shielded enclosure which houses aninspection system. While the tire is on the centering table it iscentered laterally by a pair of arms which move inwardly to engageopposite sides of the tire tread. The centering arms also serve assensors to a measure the outer diameter of the tire. Once the tire hasbeen centered, a width sensor bar descends to measure the width of thetire.

The tire diameter and width information is transmitted to a controlconsole where it is used in pre-positioning several movable componentsof the tire inspector to effect the most efficient handling of the tire.When a tire inspection already underway within the enclosure iscompleted, doors on opposite sides of the enclosure open tosimultaneously discharge the inspected tire and admit the tire from thecentering table.

As the tire to be inspected enters the enclosure, the conveyor system onwhich it travels is elevated or lowered as need be to position the tirewith its center plane in a predetermined inspection plane. Before thetire reaches the inspection station, first and second sets of spindleson opposite sides of the tire are positioned to just clear the tirewidth for ready insertion into the tire. Similarly, the X-ray source andan X-ray sensitive receiving unit are moved to optimum positions whichwill clear the inner and outer tire diameters. A traveling positioningswitch assembly moves to a position where it will stop the conveyor withthe axis of the tire along a predetermined line. In short, by the timethe tire reaches the inspectin station, all is in readiness to receivethe tire and to initiate its inspection.

As the tire reaches the inspection station, the doors to the shieldedenclosure close. The sets of spindles carried on arms arranged in across-crossed, scissors fashion move axially into the tire and pivotlaterally to engage the tire bead. Since the center plane of the tire isalready aligned with the inspection plane, the tire need not be furthermoved to initiate inspection.

As soon as the spindles have engaged the tire beads, the output windowof the X-ray tube is uncovered and the tube begins to move into the tireannulus. The main conveyor which carried the tire to the inspectionstation moves away from the tire, and sections of the main conveyor foldout of the way to provide space for full range movement of the receivingunit. The sets of spindles move away from each other a short distance tospread the tire beads. The movements of all these components areindependently controlled and a number of the movements take placesimultaneously to minimize set-up time.

In the preferred embodiment, the inspection system employs an X-raysource and an X-ray imaging unit. One feature of the apparatus is itsuse of a retractable X-ray tube which operates continuously to emitX-radiation. The tube does not shut down when retracted or when movingbetween its retracted and extended positions. A movable shield assemblycovers the tube when it is retracted so the doors to the enclosure canbe opened without leaking radiation. The tube is prevented from beinguncovered when the doors are open, and the doors cannot be opened whenthe tube is uncovered.

The use of a continuously operating tube permits the use of a much lesscomplicated generator system. If the tube were to turn off and onbetween inspection operations, the generator would have to be providedwith a more complicated automatic system permitting its start-up inminimal time without drawing excessively high current. By running thetube continuously, a less complex, manual generator start-up system canbe used and no time is lost between inspections waiting for warm-up ofthe X-ray system. Continuous tube filament operation may extend tubeoperating life in that it avoids the thermal shock of cooling down whenturned off and heating up when turned on. Keeping the filament hot maymake it less subject to breakage due to vibration since the filament ismore ductile when hot.

Since the X-ray tube is operating at the time of its insertion into thetire, X-ray inspection is begun immediately. The spindles are rotated torevolve the tire. The imaging unit forms an image of tire portions beinginspected on a control console screen.

When inspection is completed the imaging unit and the X-ray tuberetract, the main conveyor repositions, the spindles retract, and thedoors open to discharge the inspected tire and receive a subsequenttire.

The inspection cycle itself can be manually controlled from the consoleor can be carried through to completion by a programmed computer in thecontrol console. Since all of the movements of the apparatus componentsare independently controllable from the control console, the operatorcan manually effect any operable program of inspection and the computercan likewise effect any operable program.

Several advantages are obtained by utilizing a closed loop computercontrol apparatus in combination with independently operable,servo-system controlled mechanism movements. First, the computer can beprogrammed to prevent operation of the apparatus in any manner that ispotentially destructive to the apparatus or dangerous. In effect, thecomputer tells the operator what things he is allowed to do, andprevents the operator from doing destructive or dangerous things.

Another advantage is that the computer can be programmed to continuouslymonitor all machine functions. If any element moves or tries to movefurther than it should, or requires a longer period of time to move thanit should, the computer shuts down the machine and provides a codedreadout analyzing the malfunction for the operator. This system has beenshown in tests to be very successful in preventing machine damage,facilitating repair of malfunctioning components, and in generalsubstantially reducing machine down time.

The several referenced cases filed concurrently with this case relate tovarious aspects of the tire inspector and its operation. The lines ofdemarcation between these several cases exist principally due to thefact that different people and groups of people contributed inventiveconcepts during the overall development.

Certain basic concepts of the system were conceived initially by oneinventor, and these concepts form the subject of the Systems Patent.Certain additional concepts together with ways of implementing the basicconcepts were conceived jointly by two inventors, and these form thesubject of the Operations Patent. Certain mechanisms and methods ofoperating these mechanisms were conceived by one inventor, and theseform the subject of the present case. The concept of using a shieldedX-ray tube operating continuously within a shielded enclosure wasdeveloped jointly through the efforts of three inventors, and this formsthe subject of the Shielded Structures Patent. The control system andits operation represents the work of two inventors, and forms thesubject of the Controls Patent.

One feature to which the present case relates is the use of controlledspindle extension pressure for controlling the force which the spindlesapply to the beads of a tire supported on the spindles in the inspectionstation.

Other features relate to the structural features of several of theoperating components in the description and claims which follow.

As will be apparent from the foregoing summary, it is a general objectof the present invention to provide a novel and improved X-ray tireinspection system.

Other objects and a fuller understanding of the invention may be had byreferring to the following description and claims taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a tire inspector apparatus constructedin accordance with the present invention and showing the relativearrangement of the major components of the apparatus;

FIG. 2 is a perspective view of the control console of the apparatusshown in FIG. 1;

FIG. 3 is an enlarged perspective view of a portion of the centeringtable, showing the centering table elevation drive system;

FIG. 4 is a perspective view of still another portion of the centeringtable, showing the centering arm assembly;

FIG. 5 is an enlarged top plan view of a portion of the centering armassembly with portions broken away to illustrate details ofconstruction;

FIG. 6 is a perspective view of still another portion of the centeringtable showing the height sensor mechanism;

FIG. 7 is an elevational view of a portion of the height sensor as seenfrom the plane indicated by the line 7--7 in FIG. 6;

FIG. 8 is a perspective view of a portion of the shielded enclosureshowing the opening through which tires are admitted to the enclosure,as seen from outside the shielded enclosure;

FIG. 9 is an enlarged plan view of the outlet door assembly as viewedfrom inside the shielded enclosure;

FIG. 10 is an elevational view of portions of the tire inspectorapparatus showing the relative arrangement of several of its components;

FIG. 11 is a top plan view of portions of the tire inspector apparatusshowing the relative arrangement of several of its components;

FIG. 12 is a perspective view of the imaging system carriage;

FIG. 13 is a perspective view of the imaging system sub-carriage;

FIG. 14 is a cross-sectional view as seen from the plane indicated bythe line 14--14 in FIG. 13;

FIG. 14A is an elevational view on an enlarged scale of a sensor systemfor protecting the screen of the imaging unit, portions of the systembeing broken away to illustrate details;

FIG. 14B is a cross-sectional view as seen from planes indicated by thebroken line 14B--14B in FIG. 14A;

FIG. 15 is a perspective view of the main conveyor;

FIG. 16 is an end elevational view of portions of the main conveyor withthe gear rack guard assembly removed;

FIG. 17 is a perspective view of the spindle carriages and theirrespective drive systems;

FIG. 18 is a cross-sectional view as seen from the plane indicated bythe line 18--18 in FIG. 17;

FIG. 19 is an enlarged cross-sectional view of one of the spindles asseen from the plane indicated by the line 19--19 in FIG. 17;

FIG. 20 is an enlarged perspective view of the X-ray carriage;

FIG. 21 is an enlarged perspective view of the X-ray sub-carrige andX-ray sub-sub-carriage together with the X-ray tube assembly;

FIG. 21A is an enlarged top plan view of portions of the X-raysub-carriage, X-ray sub-sub-carriage, and the spindles showing in solidlines the position of these components for insertion into a tire, andshowing in phantom the internal diameters of the largest and smallesttires inspected by the system;

FIGS. 21B and 21C are schematic top plan views of tires positioned inthe inspection station illustrating the path of movement of the X-raytube focal spot after the X-ray tube has been inserted into such tire;

FIG. 22 is a perspective view of the traveling limit switch assembly;

FIG. 23A, 23B are schematic diagrams tabulating the several electricalinputs to the control console from limit switches and photocells;

FIG. 24 is a schematic electrical diagram tabulating the several inputsto the control console from potentiometers and a tachometer;

FIGS. 25A, 25B are schematic electrical diagrams tabulating the severaloutputs from the control console to motors, solenoid operated valves,and a pressure regulator;

FIG. 26 is a schematic block diagram of the several components of thecomputer of the control system; and,

FIGS. 27A-27E present a schedule of the preferred sequence of operationthe tire inspector apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, a tire inspector apparatus is shown generally bythe numeral 100. The apparatus 100 includes a shielded enclosure 275which houses several automated components, as will be explained. Acentering table 120 and a control console 1300 are positioned outsidethe enclosure 275.

The apparatus 100 is installed between two conventional belt conveyorsections 101, 102 driven, respectively, by motors 101M, 102M. Theconveyor 101 is operated intermittently to deliver tires one at a timeonto the centering table 120. Once a tire has been received on thecentering table 120, its size is sensed and it is centered for admissionto the enclosure 275. Once a tire has been admitted to the enclosure275, it is spindled for rotation and X-ray inspected during rotation, aswill be explained. Inspected tires are discharged from the enclosure 275onto the conveyor section 102 which runs continuously. The operation ofthe apparatus 100 and the conveyor 101 is controlled from the controlconsole 1300.

The description which follows is divided into several sections, eachtreating a specific portion of the apparatus 100. The latter sectionsdescribe the operation of the apparatus 100.

THE CENTERING TABLE 120

The centering table 120 includes an upstanding frame 130 which underliesand supports a driven roller conveyor 140. The conveyor 140 includes awelded, generally rectangular frame 141 which journals opposite endregions of a plurality of cylindrical rolls 142. A motor 142M isdrivingly connected to the rolls 142 by a series of roller chains 143reeved around sprockets 144 to concurrently drive the rolls 142.

The right end of the roller conveyor 140, as viewed in FIG. 1, ispivotally connected to the upstanding frame 130. Depending flanges 131carried on opposite sides of the conveyor frame 141 extend alongsideupstanding flanges 132 carried on the right end region of the centeringtable frame 130. Pins 133 extend through aligned holes in the flanges131, 132 to form a pivotal connection between the roller conveyor 140and centering table frame 130.

The left end of the roller conveyor 140 can be raised and loweredrelative to the centering table frame 130. Referring to FIG. 3, a rackand pinion drive system, indicated generally by the numeral 145, isinterposed between the centering table frame 130 and the left end of theroller conveyor 140. Two pairs of spaced, depending flanges 146 arecarried by the conveyor frame 141. A pair of vertically oriented gearracks 147 have upper end regions which extend between the spaced flanges146. Pins 148 extend through aligned holes in the flanges 146 and thegear racks 147 to pivotally connect the gear racks 147 to the conveyorframe 141. Guide rollers 149 rotatably mounted on the centering tableframe 130 engage the gear racks 147 and confine their movement tovertical directions.

Two pairs of gears 150, 151 mesh with the gear racks 147. An idler shaft152 rotatably carried by the frame 130 mounts the upper pair of gears150 for concurrent rotation. A drive shaft 153 rotatably carried by theframe 130 mounts the lower pair of gears 151 for concurrent rotation. Amotor 140M drivingly connects with the shaft 153.

Lowering and raising of the left end of the roller conveyor 140 iseffected by the motor 140M. When the motor 140M rotates the drive shaft153 in one direction, the meshing engagement between the gears 151 andthe gear racks 147 will cause the left end of the conveyor 142 to raise.When the motor 140M drives the shaft 153 in the opposite direction, theleft end of the conveyor 140 will lower.

The height of the left end of the conveyor 140 is monitored by apotentiometer 140P. The potentiometer 140P is carried by a bracket 154secured to the centering table frame 130. The potentiometer 140P has arotatable stem 155 which carries a sprocket 156. A roller chain 157 isreeved around the sprocket 156 and around a drive sprocket 157 carriedon the drive shaft 153. Rotation of the drive shaft 153 by the motor140M effects concurrent rotation of the potentiometer stem 155. Asuitable electrical cable (not shown) connects the potentiometer withthe control console 1300. The potentiometer 140P provides a resistancewhich varies to provide a variation in a signal voltage indicating theheight of the conveyor 140.

A pair of limit switches 140S₁, 140S₂ are provided to sense when theleft end of the conveyor 140 is at the lowermost and uppermost ends ofits range of travel. The switches 140S₁, 140S₂ are supported on theframe 130. An arm 159 secured to one of the gear racks 147 selectivelyengages one of the switches 140S₁, 140S₂ when the conveyor 140 is at theupper or lower ends of its range of travel. The switches 140S₁, 140S₂are each electrically connected by suitable conductors (not shown) tothe console 1300 to provide a step variation in a signal voltage.

THE CENTERING TABLE CENTERING MECHANISM 160

A centering mechanism, indicated generally by the numeral 160 in FIGS. 1and 4, is provided to laterally center tires on the conveyor 140 foradmission to the shielded enclosure 275. The centering mechanism 160 iscarried on the conveyor frame 141 for movement with the conveyor frame141 as the conveyor 140 pivots about the pins 133 connecting its rightend with the centering table frame 130.

Referring to FIG. 4, a pair of spaced upstanding arm assemblies 161 arecarried on opposite sides of the roller conveyor 140. The arm assemblies161 are movable toward and away from each other to engage and disengageopposite sides of a tire received on the centering table 120. The armassemblies 161 include support plates 162 carried on brackets 163. Thebrackets 163 depend between some of the rolls 142. Lower end regions ofthe brackets 163 connect with a pair of supports 164.

A guide rod 167 is supported at opposite ends by the conveyor frame 141.The supports 164 are slidably carried on the guide rod 167. A threadedrod 169 is journaled for rotation near opposite ends by bearing blocks170 secured to the conveyor frame 141. The threaded rod 169 has righthand threads 169R which drivingly connect with one of the arm assemblies161, and left hand threads 169L which drivingly connect with the otherarm assembly 161. When the rod 169 is rotated in one direction, the armassemblies 161 move toward each other. When the rod 169 is rotated inthe other direction, the arm assemblies 161 move away from each other.

A timing belt pulley 171 and a sprocket 172 are secured to one endregion of the threaded rod 169. A toothed timing belt 173 is reevedaround the pulley 171 and around a pulley 174 carried on one of a stubshaft 175. A bearing block 176 journals the stub shaft 175. A V-beltpulley 177 is carried on the other end region of the stub shaft 175.

A reversible centering arm drive motor 161M is provided to rotate thethreaded rod 169. A V-belt 178 is reeved around a pulley 179 carried onthe drive shaft of the motor 161M, and around the pulley 177. The belts173, 178 drivingly connect the motor 161M to the threaded rod 169 tomove the centering arms 161 toward and away from each other.

A roller chain 180 is reeved around the sprocket 172 and around asprocket 181 carried on one end region of a shaft 182. The shaft 182extends across the width of the frame 141. A pair of bearing blocks 183(only one is shown in FIG. 4) are secured to opposite sides of the frame141 to journal the shaft 182.

The shaft 182 provides a drive on opposite sides of the conveyor 140 fora movable photocell sensing system, as will be described. Identicalchain drives connect with the shaft 182 on opposite sides of theconveyor 140 to drive this photocell system. Only one of these drives isshown in FIG. 4 as including a sprocket 184 carried on the shaft 182, asprocket 187 rotatably carried on the conveyor frame 141, and rollerchain 185 reeved around the sprockets 184, 187. Identical sprockets 184,187 and an identical roller chain 185 (not shown) are provided on theopposite side of the conveyor 140.

The inward and outward positioning of the centering arms 161 ismonitored by a potentiometer 161P. The potentiometer 161P is carried bya bracket 189 secured to the frame 141. The potentiometer 161P has arotatable stem which carries a sprocket 186. A roller chain 188 isreeved around the sprocket 186 and around a drive sprocket 187aconnected to one of the sprockets 187. Rotation of the sprocket 187a bythe motor 161M effects concurrent rotation of the stem of thepotentiometer 161P. A suitable electrical cable (not shown) connects thepotentiometer 161P with the control console 1300. The potentiometer 161Pprovides a resistance which varies to provide a variation in a signalvoltage indicating the position of the centering arms 161.

A pair of limit switches 161S1, 161S2 are provided to sense when thecentering arms 161 are at the inward and outward ends of their range oftravel. The switches 161S₁, 161S₂ are supported on the frame 141, andare selectively engaged by one of the supports 164 when the centeringarms 161 are at the inward or outward ends of their range of travel. Theswitches 161S₁, 161S₂ are electrically connected by suitable conductors(not shown) to the control console 1300 to provide a step variation in asignal voltage.

Referring to FIG. 5, each of the centering arm assemblies 161 carries amovable sensing plate 190. Projections 162a, 190a formed on the plates162, 190 extend toward each other and are connected by pins 191 to forma pivotal connection between lower regions of the plates 162, 190. Capscrews 192 extend through slots 162b formed in the plates 162 and arethreaded into the plates 190 to limit the relative pivotal movement ofthe plates 162, 190 in directions away from each other. Compression coilsprings 193 carried on the cap screws 192 bias the plates 162, 190 awayfrom each other.

The centering arm assemblies 161 carry limit switches 190S₁, 190S₂. Theswitches 190S₁, 190S₂ are carried on brackets 194 secured to the plates162. The switches 190S₁, 190S₂ have actuating plungers which projectthrough apertures in the plates 162 and into engagement with the plates190. When the plates 190 engage a tire positioned on the conveyor 140,the plates 190 pivot toward the plates 162 actuating the switches 190S₁,190S₂. The switches 190S₁, 190S₂ are electrically connected in seriesand are connected by suitable conductors (not shown) to the controlconsole 1300 to provide a step variation in a signal voltage.

THE CENTERING TABLE TIRE WIDTH SENSOR MECHANISM

The width of a tire received on the centering table 120 is sensed by atire width sensor assembly 195. Referring to FIGS. 1 and 6, the widthsensor assembly 195 has an upstanding frame including four legs 196welded to the conveyor frame 141 for movement with the conveyor frame141 as the conveyor 140 pivots about the pins 133 connecting its rightend with the centering table frame 130.

Two laterally extending members 197 are welded between the legs 196.Four cross bars 198, 199, 200, 201 are welded between the members 197.Two depending bars 202, 203 have their upper ends welded to the members197. A cross bar 204 is welded to the depending bars 202, 203 and hasopposite end regions which project beyond the sides of the dependingbars 202, 203. Mounting blocks 205 are welded to the members 196, 197 atpositions above the cross bar 204.

A sensor bar 210 is movably carried at a laterally centered positionoverlying the roller conveyor 140. The sensor bar 210 includes a rigidplate 211 supported on two spaced, upstanding gear rackets 212, 213. Apair of roller bearing assemblies 214, 215 are secured to the cross bar204 and to the mounting blocks 205, respectively. The roller bearingassemblies 214, 215 engage the gear racks 212, 213 and act as guideslimiting the movement of the gear racks to travel in verticaldirections.

A pair of gears 216, 217 mate with the gear racks 212, 213. The gears216, 217 are secured to opposite end regions of a shaft 218. A pair ofbearing blocks 219, 220 carried on the depending bars 202, 203 journalthe shaft 218 for rotation. Another pair of bearing blocks 221, 222carried on two the legs 196 journal an idler shaft 223. A pair ofsprockets 224, 225 are carried on the shafts 128, 223 respectively. Aroller chain 226 is reeved around the sprockets 224, 225. Movement ofthe roller chain 226 rotates the shafts 218, 223 together with the gears216, 217, causing the gear racks 212, 213 to raise and lower the plate211.

Raising and lowering of the plate 211 is effected by a pneumatic motor190M. The motor 190M includes a cylindrical tube 230 supported nearopposite ends on the cross bars 199, 200. A piston 231 is movablymounted in the tube 230. A pair of pulleys 232 are positioned onopposite ends of the tube 230. A flexible cable 233 is reeved around thepulleys 232 and connects with the piston 231. When pressurized air isadmitted to the tube 230 on one side or the other of the piston 231, thepiston 231 will move through the tube 230, causing the cable 233 torotate the pulleys 232. A connector block 234 connects the cable 233 tothe roller chain 226. When the piston 231 moves the cable 233, the chain226 will move causing the gear racks 212, 213 to move vertically.

The vertical positioning of the sensor bar 210 is monitored by apotentiometer 195P. A bracket 235 mounts the potentiometer 195P on oneof the legs 196 below the bearing block 221. The potentiometer 195P hasa rotatable stem 236 which carries a sprocket 237. A roller chain 238 isreeved around the sprocket 237 and around a sprocket 239 carried on theidler shaft 223. As the idler shaft 223 rotates in response to movementof the chain 226, the potentiometer stem 236 is concurrently rotated tovary the resistance of the potentiometer 195P. A suitable electricalcable (not shown) connects the potentiometer 195P to the control console1300 to provide a variation in a signal voltage indicating the positionof the sensor bar 210. When the sensor bar 210 has been lowered intoengagement with a tire positioned on the centering table 120, thepotentiometer 195P provides an indication to the computerized controlconsole 1300 of the width of the tire.

The sensor bar 210 carries a limit switch 195S₁ which senses when thesensor bar has engaged a tire positioned on the centering table.Referring to FIG. 7 a plate 240 has its left end pivotally connected tothe plate 211. A bracket 241 is secured to one end region of the plate240 and is pivotally connected to one end region of the plate 211. Thebracket 241 carries a stop (not shown) which prevents the plates 211,240 from pivoting away from each other to a greater extent than is shownin FIG. 7. A compression coil spring 242 is interposed between theopposite end regions of the plates 211, 240 to bias the plates 211, 240away from each other. A bracket 243 mounts the limit switch 195S1 atopthe plate 211. The limit switch 195S1 has an actuating plunger 244 whichdepends through a hole 245 in the plate 211. The bottom end of theplunger 244 engages the top surface of the plate 240.

When the sensor bar 120 is lowered into engagement with a tirepositioned on the centering table, the plate 240 pivots upwardly movingthe plunger 244 and actuating the limit switch 195S1 to provide a stepvariation in a signal voltage. A suitable electrical cable (not shown)connects the switch 195S1 to the control console 1300.

CENTERING TABLE CONVEYOR CONTROLS

Referring to FIG. 6, two photocells 142P1, 142P2 are carried on one ofthe legs 196 opposite to light sources 250, 251 carried another of thelegs 196. Suitable electrical cables (not shown) connect the photocells142P1, 142P2 to the control console 1300 to provide step variations in asignal voltage to indicate the presence or absence of an object betweenone or both of the light sources 250, 251 and their associatedphotocells 141P1, 141P2. As will be explained in greater detail, when atire is received on the centering table conveyor 140, the conveyor rolls142 continue to drive until the tire interrupts one or both of the lightbeams received by the photocells 142P1, 142P2. When either or both ofthe photocells 142P1, 142P2 sense the presence of a tire, the conveyordrive motor 142M is de-energized.

Referring to FIG. 1, a stationary photocell 101P₁ is supported on theframe 141 near the right end of the roller conveyor 140. A light source252 is supported on the frame 141 opposite the photocell 101P₁. Thephotocell 101P₁ is connected through suitable electrical cables (notshown) to the control console 1300 to provide a step variation in asignal voltage indicating of the presence or absence of a tire on theconveyor section 101. The conveyor drive motor 101M is controlled at thecontrol console 1300 in response to signals from the photocell 101P₁ tostop and start the conveyor 101 at appropriate times to effect feedingof tires one at a time onto the centering table conveyor 140.

Referring to FIGS. 1 and 4, two movable photocells 161P₁, 161P₂ arecarried in a housing 255 on one side of the conveyor 140. Acorresponding pair of movable light sources 256, 257 carried in ahousing 258 on the opposite side of the conveyor 140. A pair of brackets259, 260 support the photocells 161P₁, 161P₂, and the light sources 256,257 respectively.

A similar pair of brackets 259 (only one is shown in FIG. 4) areprovided on opposite sides of the conveyor 140 to movably mount thephotocells 161P₁, 161P₂ and the light source 256, 257 for concurrentmovement. The brackets 259 are each slidably carried on a pair of guiderods 261 which extend longitudinally of the conveyor 140. The brackets259 are secured to the roller chains 185 for movement in response tooperation of the centering arm drive motor 161M. Suitable electricalcables, not shown, connect the photocells 161P1, 161P2 to the controlconsole 1300 to provide step variations in a signal voltage indicatingthe presence or absence of an object between one or both of the lightsources 256, 257 and their associated photocells 161P1, 161P2.

In operation, the photocells 161P1, 161P2 and the light sources 256, 257move toward the shielded enclosure 275 when the centering arms 161 movetoward each other, and vice versa. The light beams which extend from thesources 256, 257 toward the photocells 161P1, 161P2 will not beinterrupted if a tire is properly positioned between the centering arms161. If the light beams are interrupted, certain indicator lights areilluminated on a fault detection display on the control console 1300, aswill be explained, to indicate that a malfunction has occurred.

THE SHIELDED ENCLOSURE 275

The shielded enclosure 275 has walls formed from lead-lined steel toprevent the escape of X-radiation from inside the enclosure. Identicalinlet and outlet openings 276 are formed on opposite sides of theenclosure. FIG. 8 shows the inlet opening 276 as viewed from outside theenclosure 275. FIG. 9 shows the outlet opening 276 as viewed from insidethe enclosure 275.

Identical door assemblies 277 including pairs of doors 278 are providedinside the enclosure 275 to concurrently open and close the openings276. The doors 278 are vertically movable and include an upper door anda lower door associated with each of the openings 276. The lower doorseach carry an upstanding lip 279 which overlaps the line of juncturebetween the upper and lower doors when the doors 278 are closed toprevent radiation leakage.

Each of the doors 278 carries an arm 280. Two limit switches 278S₁,278S₂ are associated with each arm 280. The limit switches 278S₁, 278S₂are selectively engaged by the arms 280 when the doors 278 are open orclosed.

A pneumatic motor 278M is associated with each door assembly 277 to openand close the doors 278. The motor 278M has a piston 281 which movesaxially depending on which end region of the motor 278M is supplied withpressurized air. Each door assembly 277 has a cable 282 with oppositeends connected to opposite ends of the piston 281. Intermediate portionsof the cables 282 are reeved around pulleys 283 carried on the innerwall of the enclosure 275. Each of the doors 278 carries two brackets284 which connect with the cables 282 to open and close the doors 278 inresponse to axial movement of the pistons 281 in the motors 278M.

A pair of photocells 278P₁, 278P₂ is associated with each of the doorassemblies 277. The photocells 278P₁, 278P₂ associated with the inletopening 276 are mounted outside the enclosure 275, as shown in FIG. 8.The photocells 278P₁, 278P₂ associated with the outlet opening 276 aremounted inside the enclosure, as shown in FIG. 9. A light source 285 isprovided for each of the photocells 278P₁, 278P₂ on the opposite side ofthe opening 276 from its associated photocell. The light sources 285associated with the inlet opening 276 are inside the enclosure 275. Thelight sources 285 associated with the outlet opening 276 are outside theenclosure 275.

When the doors 278 are open, the photocells 278P₁, 278P₂ receive lightfrom the sources 285. Suitable electrical cables (not shown) connect thephotocells 278P₁, 278P₂ to the control console 1300 to provide stepvariations in a signal voltage indicating the presence or absence of anobject between one or more of the light sources 285 and their associatedphotocells 278P₁, 278P₂. If the photocells 278P₁, 278P₂ do not receivelight from the sources 285 at a time when the doors 278 are to be movedfrom an open to a closed position, the doors 278 are prevented fromclosing, as will be explained.

THE MAIN FRAME 320

Referring to FIGS. 1, 10 and 11, a main frame 320 includes fourupstanding columns 321, 322, 323, 324. A pair of beams 325, 326 aremounted atop the columns 321, 322 and 323, 324.

The side of the main frame 320 defined by the columns 321, 322 and thebeam 325 will be referred to as the "first side." The side defined bythe columns 323, 324 and the beam 326 will be called the "second side."The side defined by the columns 322, 324 will be referred to as the backside or rear of the main frame 320. The side defined by the columns 321,323 is considered to be the front.

The first and second sides of the main frame are of substantiallyidentical construction, one being the mirror image of the other. Severalcross members, one of which is indicated by the numeral 327,interconnect the first and second sides to form a rigid frame.

THE IMAGING SYSTEM CARRIAGE 340

Referring to FIG. 12 in conjunction with FIGS. 1, 10, and 11, an imagingsystem carriage 340 is movably supported on the main frame 320. Thecarriage 340 is a welded structure including four full length uprights341, 342, 343, 344 and four shorter uprights 345, 346, 347, 348. Theuprights 341, 342, 345, 346 are interconnected by four full lengthmembers 349, 350, 351, 352 and by a shorter member 353, to define afirst side of the carriage 340. The uprights 343, 344, 347, 348 areinterconnected by four full length members 354, 355, 356, 357 and by ashorter member 358, to define a second side of the carriage 340. Sixcross members 359, 360, 361, 362, 363, 364 extend between the first andsecond sides of the carriage 340 to form a rigid carriage structure.

The carriage 340 is positioned between the main frame beams 325, 326with the side members 350, 355 paralleling the beams 325, 326. A pair ofguide rods 365, 366 are carried by the beams 325, 326. Two pairs ofbearing blocks 367, 368 are carried on the side members 350, 355. Thebearing blocks 367, 368 slidably receive the guide rods 365, 366 tomovably mount the imaging system carriage 340 on the main frame beams325, 326.

A pair of gear racks 369, 370 are carried on the main frame beams 325,326. A pair of gears 371, 372 carried on a shaft 373 mesh with thetoothed gear racks 369, 370. The shaft 373 is journaled by a pair ofbearing blocks 374 carried on the carriage uprights 341, 343. Areversible drive motor assembly 340M carried on the cross member 361drivingly connects with the shaft 373 to move the imaging systemcarriage 340 inwardly and outwardly along the main frame beams 325, 326.

The inward and outward position of the imaging system carriage 340 ismonitored by a potentiometer 340P. The potentiometer 340P is carried bya bracket 375 secured to the cross member 361. The potentiometer 340Phas a rotatable stem 376 which carries a sprocket 377. A roller chain378 is reeved around the sprocket 377 and around a drive sprocket 379carried on the shaft 373. Rotation of the shaft 373 by the motor 340Meffects concurrent rotation of the potentiometer stem 376. A suitableelectrical cable (not shown) connects the potentiometer 340P with thecontrol console 1300. The potentiometer 340P provides a resistance whichvaries to provide a variation in a signal voltage indicating theposition of the imaaging system carriage 340.

A pair of limit switches 340S₁, 340S₂ are provided to sense when theimaging system carriage 340 is at the inner and outer ends of its rangeof travel. The switches 340S₁, 340S₂ are supported on the main framebeam 326. One of the bearing blocks 368 selectively engages one of theswitches 340S₁, 340S₂ when the imaging system carriage 340 is at theinner or outer ends of its range of travel. The switches 340S₁, 340S₂are electrically connected by suitable conductors (not shown) to thecontrol console 1300 to provide a step variation in a signal voltage.

Two C-shaped arms 380, 381 are carried by the imaging system carriage340. the C-shaped arms define a pair of curved trackways which, as willbe explained, support and guide the movement of an imaging systemsub-carriage 390. A pair of roller chains 382, 383 extend along theouter surfaces of the C-arms 380, 381. Opposite ends of the rollerchains 382, 383 are secured by brackets (not shown) to the end regionsof the C-arms 380, 381.

THE IMAGING SYSTEM SUB-CARRIAGE 390

Referring to FIGS. 12 and 13, an imaging system sub-carriage 390 iscarried on the C-arms 380, 381. The subcarriage 390 includes a weldedbase formed from two spaced, parallel arms 391, 392 connected by a plate393. A pair of upstanding brackets 395, 396 and a pair of dependingbrackets 397, 398 are welded to the arms 391, 392. The brackets 395,396, 397, 398 carry rollers 399 which engage the C-arms 380, 381 tomovably mount the sub-carriage 390 on the C-arms 380, 381.

The upstanding brackets 395, 396 each rotatably mount a pair of idlersprockets 401. A drive shaft 402 is journaled by the brackets 395, 396.A pair of drive sprockets 403 are carried on opposite end regions of thedrive shaft 402. The roller chains 382, 383 are reeved around the idlersprockets 401 and around the drive sprockets 403, as best seen in FIG.13.

A reversible drive motor assembly 390M is mounted on the plate 393. Themotor assembly 390M has an output shaft 404 which carries a sprocket405. A roller chain 406 is reeved around the sprocket 405 and around asprocket 407 carried on the shaft 402. When the motor 390M drives theshaft 402 in one direction, the sub-carriage 390 moves up the C-arms380, 381. When the shaft 402 is driven in the opposite direction, thesub-carriage 390 moves down the C-arms 380, 381.

The position of the sub-carriage 390 along the C-arms 380, 381 ismonitored by a potentiometer 390P. The potentiometer 390P is carried bya bracket 408 secured to the plate 393. The potentiometer 390P has arotatable stem 409 which carries a sprocket 410. A roller chain 411 isreeved around the sprocket 410 and around a drive sprocket 412 carriedon the drive shaft 402. Rotation of the drive shaft 402 by the motor390M effects concurrent rotation of the potentiometer stem 409. Asuitable electrical cable (not shown) connects the potentiometer 390Pwith the control console 1300. The potentiometer 390P provides aresistance which varies to provide variation in a signal voltageindicating the position of imaging system sub-carriage 390 along theC-arms 380, 381.

Referring to FIG. 12, a pair of limit switches 390S1, 390S2 are providedon opposite ends of the C-arms 381 to sense when the imaging systemsub-carriage 390 is at the upper and lower ends of its range of travel.The switches 390S1, 390S2 are selectively engaged by the brackets 396,398 when the sub-carriage 390 is at the upper or lower ends of its rangeof travel. The switches 390S1, 390S2 are electrically connected bysuitable conductors (not shown) to the control console 1300 to provide astep variation in a signal voltage.

A pair of guide rods 415, 416 are supported by the sub-carriage arms391, 392. The guide rods 415, 416 extend parallel to the arms 391, 392and serve to movably support an imaging system sub-sub-carriage 420.

THE IMAGING SYSTEM SUB-SUB-CARRIAGE 420

Referring to FIGS. 13 and 14, the sub-sub-carriage 420 includes a weldedframework formed by a pair of uprights 421, 422, a pair of arms 423,424, a pair of brace members 425, 426 and a cross member 427. A pair oflineal bearings 417, 418 slidably receive the guide rods 415, 416 tomovably mount the sub-sub-carriage 420 on the arms 391, 392 of thesub-carriage 390.

A pair of idler sprockets 428 are rotatably mounted on the sub-carriagearms 391, 392. A pair of roller chains 429 are reeved around thesprockets 428 and around a pair of sprockets 430 (only one is shown inFIG. 14) carried on opposite end regions of a shaft 431. A pair ofbrackets 432 carried on the bearings 429, 430 connect with the rollerchains 429.

A reversible drive motor assembly 420M is secured to the underside ofthe plate 393. The motor 420M has an output shaft 431a which carries asprocket 431b. A roller chain 433 is reeved around the sprocket 431b andaround a sprocket 434 carried on the shaft 431. When the motor 420Mdrives the shaft 431 in one direction, the sub-sub-carriage 420 movesinwardly along the guide rods 415, 416. When the shaft 431 is driven inthe other direction, the sub-sub-carriage 420 moves outwardly along theguide rods 415, 416.

The position of the sub-sub-carriage 420 is monitored by a potentiometer420P. The potentiometer 420P is carried by a bracket 435 secured to theunderside of the plate 393, as best seen in FIG. 13. The potentiometer420P has a rotatable stem 436 which is connected to the motor outputshaft 431a. A suitable electrical cable (not shown) connects thepotentiometer 420P with the control console 1300. The potentiometer 420Pprovides a resistance which varies to provide a variation in a signalvoltage indicating the position of the sub-sub-carriage 420 along theguide rods 415, 416.

A pair of limit switches 420S1, 420S2, are provided to sense when thesub-sub-carriage 420 is at the inner and outer ends of its range oftravel. The switches 420S1, 420S2 are supported on the sub-carriage arm392. The switches 420S1, 420S2 are selectively engaged by the bearing430 carried on the guide rod 415 when the sub-sub-carriage 420 is at theinner or outer ends of its range of travel. The witches 420S1, 420S2 areelectrically connected by suitable conductors (not shown) to the controlconsole 1300 to provide a step variation in a signal voltage.

The Imaging Unit 440

An imaging unit 440 is carried on the sub-sub-carriage 420. The imagingunit 440 is a conventional imaging system of the type which is capableof producing an output signal representative of an image formed byX-radiation which has passed through a tire being inspected and isreceived on imaging screen 422.

In the preferred embodiment, the imaging unit 440 is an imaging systemof the type sold by Old Delft Corporation of America, Fairfax, Virginia22030, under the trademark DELCALIX with 121/2 inch screen and ISOCONtype S video tube. Suitable electrical conductors (not shown) connectthe imaging unit 440 with the control console 1300.

Referring to FIGS. 14A and 14B, a "halo" safety switch assembly isprovided around the input screen of the imaging unit 440 to sense thepresence of an object which could do damage to the imaging unit 440. Thesafety switch assembly includes a metal ring 441 movably supported at aposition in front of the imaging screen 442. Three limit switches 440S1,440S2, 440S3 are carried on a bracket 444 second to the imaging unit440. The switches 440S1, 440S2, 440S3 have spring actuators 445 whichare actuated if moved in any direction. The ring 441 is carried on theactuators 445. The limit switches 440S1, 440S2, 440S3 are electricallyconnected by a suitable cable (not shown) to the control console 1300 toilluminate certain malfunction indicator lights on the console if thering 441 is moved by an object in close proximity to the imaging unit440.

A photocell 440P1 is carried on the bracket 444. A light source 447aimed at the photocell 440P1 is carried on the opposite side of thebracket 444 to provide a beam of light which extends across the screen442. The photocell 440P1 is connected by a suitable cable (not shown) tothe control console 1300 to operate in series with the switches 440S1,440S2, 440S3 to illuminate certain malfunction indicator lights if thebeam of light from the light source 447 to the photocell 440P1 isinterrupted.

THE MAIN CONVEYOR 450

Referring to FIGS. 15 and 16 in conjunction with FIGS. 1, 10 and 11, amain conveyor assembly 450 is carried by the main frame 320. Theconveyor 450 includes a horizontally disposed frame 451 which rotatablysupports a series of rolls 452, 453, 454, 455. A drive motor 452Mcarried beneath the frame 451 in the vicinity of the column 324 isdrivingly connected to all the rolls 452, 453, 454, 455 to rotate therolls and feed tires along the conveyor 450.

The rolls 452 extend the full width of the conveyor 450 and haveopposite end regions journaled by the frame 451. The rolls 453, 454 areshorter than the rolls 452 and have opposite ends journaled by the frame451. The rolls 455 are shorter than the rolls 452 and have endsjournaled in two movable drop-down frame structures 456.

The frame structures 456 are pivotally mounted on the frame 451 formovement about the axis of the two farthest spaced rolls 455. The framestructures 456 are movable from an elevated position shown in solidlines in FIG. 15 to a lowered position shown in phantom in FIG. 15.

A pair of pneumatic motors 456M are provided for raising and loweringthe movable frame structure 456. The motors 456M are pneumatic cylinderscarried by the frame 451 and have extensible pistons 457 connected tothe frame structures 456. When the pistons 457 are extended, the framestructures 456 assume their elevated position. When the pistons 457 areretracted, the frame structues 456 assume their lowered position.

Two pairs of limit switches 456S₁, 456S₂ are provided to sense when theconveyor frame structures 456 are elevated or lowered. The switches456S₁, 456S₂ are supported on the frame 451, and have actuators whichare selectively engaged by the frame structures 456 when the framestructures are elevated or lowered. The switches 456S₁, 456S₂ are eachelectrically connected by suitable conductors (not shown) to the controlconsole 1300 to provide a step variation in a signal voltage.

The conveyor frame 451 together with the movable frame sections 456 aremovably mounted on the main frame 320 for movement in verticaldirections. Four pneumatic motors 451M are supported on gear racks 460.The motors 451M are pneumatic cylinders having extensible pistons 461connected to corner regions of the rectangular frame 451. When thepistons 451 extend, the conveyor frame 451 is raised relative to thegear racks 460. When the pistons 461 retract, the conveyor frame 451 islowered relative to the gear racks 460.

Referring to FIG. 16 a pair of limit switches 451S₁, 415S₂ are providedto sense when the main conveyor frame 451 is at the upper and lower endsof its range of travel. The switches 451S₁, 451S₂ are supported on abracket 462 carried by the frame 451. An arm 463 is secured to one ofthe motor housings 451M and selectively engages one of the switches451S₁, 451S₂ when the conveyor frame 451 is at the upper or lower endsof its range of travel relative to the gear racks 460. The switches451S₁, 451S₂ are electrically connected by suitable conductors (notshown) to the control console 1300 to provide a step variation in asignal voltage indicating the position of the conveyor frame 451.

A pair of welded cross-member structures 470 have opposite end regionsconnected to the main frame columns 321, 322, 323, 324. A pair ofshields 471 are secured to the cross-member structures 470 to shroudlower portions of the gear racks 460.

Referring to FIG. 16, one of the cross-member structures 470 is shownwith the shield 471 removed. Each of the gear racks 460 is engaged by apair of gears 472. The gears 472 are carried on opposite end regions ofshafts 473. The shafts 473 are journaled by bearing blocks 474 carriedon the cross-member structure 470. A plurality of rollers 475 carried onthe cross-member structure 470 engage the gear racks 460 mounting thegear racks 460 for vertical movement relative to the main frame 320.

Referring to FIG. 11, one of the shafts 473 on each side of the mainframe 320 is drivingly connected through right angle gear boxes 476 to adrive shaft 477. A drive motor assembly 460M is provided for rotatingthe shafts 473, 477. The drive motor 460M has an output shaft 480 whichcarries a sprocket 481. A drive chain 482 is reeved around the sprocket481 and around a sprocket 483 carried on the drive shaft 477. When thedrive motor 460M rotates the shafts 473 in one direction, the gear racks460 are elevated relative to the main frame 320. When the drive motor460M rotates the shafts 473 in the opposite direction, the gear racks460 are lowered relative to the main frame 320.

Referring to FIG. 16, four auxiliary gear racks 490 have their upper endregions connected to the conveyor frame 451. A plurality of rollers 491carried on the cross-member assemblies 470 engage the auxiliary gearracks 490 and mount them for vertical movement relative to the crossmembers 470. Each of the auxiliary gear racks 490 is engaged by a pairof gears 492. The gears 492 are carried on opposite end regions ofshafts 493. The shafts 493 are journaled by bearing blocks 494 carriedon the cross-member structures 470. The auxiliary gear racks 490 serveto keep the conveyor frame 451 level when it moves up and down relativeto the gear racks 460 under the influence of the pneumatic cylinders451M.

The vertical position of the gear racks 460 is monitored by apotentiometer 46OP. The potentiometer 460P is carried by a bracket 495secured to one of the cross-members 470, as best seen in FIG. 16. Thepotentiometer 460P has a rotatable stem 496 which carries a sprocket497. A roller chain 498 is reeved around the sprocket 497 and around asprocket 499 on one of the shafts 473. Roration of the shafts 473 by themotor 460M effects concurrent rotation of the potentiometer stem 496. Asuitable electrical cable (not shown) connects the potentiometer 460Pwith the control console 1300. The poentiometer 460P provides aresistance which varies to provide a variation in a signal voltageindicating the height of the gear racks 460.

A pair of limit switches 460S1, 460S2 are provided to sense when thegear racks 460 are at the upper or lower ends of their range of travel.The switches 460S1, 460S2 are supported on one of the cross-memberstructures 470 as best seen in FIG. 16. An arm 489 carried on one of thegear racks 460 selectively engages one of the switches 460S1, 460S2 whenthe gear racks 460 are at their upper or lower ends of their range oftravel. The switches 460S1, 460S2 are electrically connected by suitableconductors (not shown) to the control console 1300 to provide a stepvariation in a signal voltage.

As will be explained in greater detail, the main conveyor 450 isinitially pre-positioned such that the rolls 452-455 are at a heightcommensurate with the rolls 142 on the left end of the centering tableconveyor 140. At the time the conveyor 450 is pre-positioned, thepistons 461 are extended from the pneumatic motors 451M. Once a tire hasbeen positioned for inspection on the conveyor 450, the pistons 461 areretracted to lower the rolls of the conveyor 450 a short distance,typically about 11/2 inches, permitting the tire to be supported onspindles for rotation.

THE SPINDLE CARRIAGES 510

Referring to FIGS. 10 and 17, a pair of spindle carriages 510 aremovably carried by the main frame 320. One of the spindle carriages 510is positioned above the main conveyor 450, and will be called the upperspindle carriage. The other carriage 510 underlies the rollers of themain conveyor 450 and will be called the lower spindle carriage. Theupper and lower carriages 510 are substantially identical, one being themirror image of the other.

Each of the carriages 510 includes a pair of support beams 511, 512. Thebeams 511 extend between the main frame columns 321, 322. The beams 512extend between the main frame columns 323, 324. The beams 511, 512support a pair of welded frame structures 513. The frame structures 513each include a pair of spaced, horizontal plates 514 interconnected byuprights 515.

The carriages 510 are supported for concurrent vertical movement towardand away from each other. Threaded bushings 516 are carried nearopposite ends of the beams 511, 512. Threaded rods 517 are received inthe bushings. The upper carriage bushings 516 are threaded with L. H.threads to accommodate L. H. threads formed on the upper end regions ofthe rods 517. The lower carriage bushings 516 are threaded with R. H.threads to accommodate R. H. threads formed on the lower end regions ofthe rods 517. When the rods 517 are rotated concurrently in onedirection, the carriages 510 move toward each other. When the rods 517are rotated concurrently in the opposite drive direction, the carriages510 move away from each other.

A reversible carriage drive motor 510M is carried by the main frame 320.The motor 510M has an output shaft which carries a sprocket 520. Aroller chain 521 is reeved around the sprocket 520 and around a sprocket522 carried on a shaft 523. The shaft 523 is journaled by bearing blocks524 secured to the main frame 320. A pair of right angle gear boxes 525drivingly connect opposite ends of the shaft 523 to a pair oftransversely extending shafts 526, 527. Two pairs of right angle gearboxes 528, 529 drivingly connect opposite ends of the shafts 526, 527 tothe threaded support rods 517.

The vertical position of the spindle carriages 510 is monitored by apotentiometer 510P. Referring to FIG. 17, the potentiometer 510P iscarried by a bracket 530 secured to the main frame beam 326. Thepotentiometer 510P has a rotatable stem 531 which carries a sprocket532. A roller chain 533 is reeved around the sprocket 532 and around adrive sprocket 534 carried on one of the rods 517. Rotation of the rods517 by the motor 510M effects concurrent rotation of the potentiometer531. A suitable electrical cable (not shown) connects the potentiometer510P with the control console 1300. The potentiometer 510P provides aresistance which varies to provide a variation in a signal voltageindicating the position of spindle carriages 510 along the rods 517.

THE SPINDLE SUPPORT ARMS 550

Four spindle support arms 550 are pivotably mounted on each of thespindle carriages 550. As is best seen in FIG. 18, the arms 550 eachhave a long leg 551 and a short leg 552. Each of the arms 550 ispivotally mounted on a separate shaft 553. The shafts 553 are journaledby bearings carried in the plates 514, as will be explained.

The arms 550 are arranged in pairs with the long legs 551 of each paircriss-crossed, and with the short legs 552 connected together by a pin554. A separate link 555 connects with each of the pins 554.

A pneumatic motor 550M is provided on each of the carriages 510 forpivoting the arms 550 about the shafts 553. Each of the motors 550M is apneumatic cylinder having an extensible piston 556. A pair of L-shapedactuating levers 557 are mounted for pivotal movement on each of thecarriages 510. Vertically extending pins 558 journaled in the plates 514carry the levers 557. One end region of each of the levers 557 connectswith one of the pistons 556. The other end region of the levers 557 isconnected to one of the links 555.

Each of the long legs 551 of the arms 550 carries a separate spindle600. The spindles 600 move with the arms 550 between the fully retractedposition shown in FIG. 18 and the fully extended position shown in FIG.17. When the pistons 556 of the motors 550M are fully extended, thespindles 600 assume their fully extended position. When the pistons 556of the motors 550M are fully retracted, the spindles 600 assume theirfully retracted position.

The pressure of the compressed air supplied to the motors 550M isregulated to control the amount of force applied by the spindles to atire being inspected. A conventional pressure regulator shown at 559 inFIG. 18, is used to vary the pressure supplied to the motors 550M. Theregulator 559 is electrically controlled through a suitable cable (notshown) which connects with the control console 1300. The regulator 559is preferably operable to adjust the pressure supplied to the motors550M from a low pressure of about 18 psi to a high pressure of about 60psi. A lesser spindle extension pressure is used with relatively smalltires than is used with relatively large tires.

The position of the spindle arms 550 is monitored by a potentiometer550P. The potentiometer 550P is carried by a bracket 558a secured to oneof the plates 514. The potentiometer 550P has a rotatable stem whichcarries a sprocket 559b. A roller chain 559c is reeved around thesprocket 559b and around a drive sprocket 559d secured to one of thespindle arms 550. Rotation of the spindle arms 550 by the motor 550Meffects concurrent rotation of the stem of the potentiometer 550P. Asuitable electrical cable (not shown) connects the potentiometer 550Pwith the control console 1300. The potentiometer 550P provides aresistance which varies to provide a variation in a signal voltageindicating the position of spindle arms 550.

A pair of limit switches 550S₁, 550S₂ are provided on each of thecarriages 510 to sense when the spindles 660 are at the fully retractedor extended ends of their range of travel. The switches 550S₁, 550S₂ aresupported on one of the plates 514. One of the levers 557 selectivelyengages one of the switches 550S₁, 550S₂ when the spindles are fullyretracted or extended. The switches 550S₁, 550S₂ are electricallyconnected by suitable conductors (not showwn) to the control console1300 to provide a step variation in a signal voltage.

Referring to FIG. 19, a typical one of the spindle arms 550 is shown incross-section. A pair of bearings 560 carried by the plates 514 journalthe shaft 553. A pair of sprockets 561 are secured by pins 562 to theupper end region of the shaft 553. A double toothed drive sprocket 563is secured by a pin 564 to an intermediate portion of the shaft 553.

The arm 550 includes two aligned bushings 565, 566 carried on the shaft553 on opposite sides of the double drive gear 563. A pair of bearings567 journal the upper bushing 565 on the shaft 563. A bearing 568journals the lower bushing 566 on the shaft 563. The short leg 552 ofthe arm 550 is welded to the upper bushing 565. The long leg 551 of thearm 550 is a tubular structure welded to both of the bushings 565, 566.

A spindle support sleeve 570 is welded to the outer end region of thelong leg 551. A pair of bearings 571 carried in the sleeve 570 journal aspindle shaft 572 for rotation. The upper end of the spindle shaft 572carries a double toothed drive sprocket 573. A double roller chain 574is reeved around the sprockets 563, 573 to rotate the spindle shaft 572in response to rotation of the shaft 553.

A tubular spindle member 575 is secured by a pin 576 to the lower endregion of the spindle shaft 572. The spindle member 575 has an annularlip 577 formed near its lower end to receive the bead of a tire duringinspection.

Referring to FIG. 17, a chain drive system indicated generally by thenumeral 580 is provided for rotating the spindles 600. The drive system580 includes a pair of roller chains 581 on each of the carriages 510which are reeved around and drivingly connect pairs of the spindlesdrive sprockets 561. Idler sprockets 582 carried on one of the plates514 tension the chain 581. Another roller chain 583 carried on each ofthe carriages 510 and is reeved around the remaining two spindle drivesprockets 561 and around a series of idler sprockets 584, and around adrive sprocket 585. The drive sprocket 585 is carried on a splined shaft586 which is journaled by bearing blocks on the main frame 320. As thespindle carriages 510 move upwardly and downwardly relative to the mainframe, the drive sprockets 585 move along the splined drive shaft 586.

Referring to FIG. 10, a spindle drive motor 600M is supported on themain frame 320. The spindle drive motor 600M drivingly connects with thesplined drive shaft 586 to rotate the shaft 586 and thereby drive thespindles 600.

The rotation of the spindles 600 is monitored by a tachometer 600P,carried atop the cross-member 327 as shown in FIG. 17. The tachometer600P has a drive shaft which carries a sprocket 591. A roller chain 592is reeved around the sprocket 591 and around a sprocket 593 carried onthe drive shaft 586. The tachometer 600P provides an output signal whichis representative of the velocity of rotation of the drive shaft 586. Asuitable electrical cable (not shown) connects the tachometer 600P withthe control console 1300.

The upper spindles 600 each carry a photocell 600P1. The lower spindles600 each carry a light source 590. The photocells 600P1 are connected bysuitable electrical conductors (not shown) to the control console 1300to provide a step variation in a signal voltage. The photocells 600Pserve in one capacity to assure that a tire is centered for spindleinsertion. Once the spindles 600 have engaged a tire for inspection, thelight beams from the sources 590 should be blocked by the tire frombeing received by the photocells 600P1.

THE X-RAY CARRIAGE

Referring to FIG. 20, an X-ray carriage 620 is movably carried by themain frame beams 325, 326. A pair of guide rods 621, 622 are carried bythe beams 325, 326. The carriage 620 has a pair of side members 623, 624which extend alongside the guide rods 621, 622. Bearing blocks 625carried by the side members 623, 624 slidably received the guide rods621, 622 to movably mount the X-ray carriage 620 on the main framesbeams 325, 326.

The X-ray carriage 620 includes a cross-member 625 which extends betweenthe side members 623, 624 a pair of upstanding members 627, 628 aresecured to the cross-member 626. A short cross-member 629 extendsbetween the upstanding members 627, 628. Four brace members 629 arewelded to the members 623, 624, 626, 627, 628 to form a rigid framestructure.

A drive motor 620M is carried by the main frame beam 325 for moving thecarriage 620 along the guide rods 621, 622. The drive motor 620 has anoutput shaft 630 which carries a sprocket 631. A roller chain 632 isreeved around the sprocket 631 and around a sprocket 633. The sprocket633 is carried on a shaft 634. A pair of bearing blocks 635 carried onthe main frame beams 325, 326 journal the shaft 634. A pair of sprockets636 are carried on the shaft 634 near opposite end regions. A pair ofroller chains 637 are reeved around the sprockets 636 and around a pairof idler sprockets 638. The idler sprockets 638 are mounted on brackets639 secured to the main frame beams 325, 326.

A pair of brackets 640 secured to the side members 623, 624 of the X-raycarriage 620 connect with the roller chains 637. When the drive motor620M rotates the shaft 634 in one direction, the carriage 620 movesinwardly along the guide rods 621, 622. When the drive motor 620Mrotates the shaft 634 in the opposite direction, the carriage 620 movesoutwardly along the guide rods 621, 622.

The position of the X-ray carriage 620 along the guide rods 621, 622 ismonitored by a potentiometer 620P. The potentiometer 620P is carried ona bracket 641 secured to the beam 325. The potentiometer 620P has a stemwhich carries a sprocket 642. A roller chain 643 is reeved around thesprocket 642 and around a sprocket 644 carried on the drive shaft 634.Rotation of the drive shaft 634 by the motor 620M effects concurrentrotation of the stem of the potentiometer 620P. A suitable electricalcable (not shown) connects the potentiometer 620P with the controlconsole 1300. The potentiometer 620P provides a resistance which variesto provide a variation in a signal voltage indicating the position ofthe carriage 620 along the guide rods 621, 622.

A pair of limit switches 620S₁, 620S₂ are carried on the main frame beam326 to sense when the carriage 620 is at the inward and outward ends ofits range of travel. The switches 620S₁, 620S₂ are selectively engagedby one of the bearing blocks 625 when the carriage 620 is in its fullyinward or outward position. The switches 620S₁, 620S₂ are electricallyconnected by suitable conductors (not shown) to the control console 1300to provide a step variation in a signal voltage.

THE X-RAY SUB-CARRIAGE 600

Referring to FIG. 21, an X-ray sub-carriage 660 is supported on theX-ray carriage 620. A pair of guide rods 661, 662 are carried by theupright members 627, 628 of the X-ray carriage 620. The X-raysub-carriage 660 includes four horizontally extending members 663interconnected by a pair of upright members 664. The horizontal members663 are apertured near one end to slidably receive the guide rods 661,662. The other end regions of the horizontal members 663 are secured toa depending mast assembly 665.

A pneumatic motor 660M is provided for moving the X-ray sub-carriage 660along the guide rods 661, 662. The motor 660M is secured to a bracket666 carried on the upright members 664. The motor 660M is a pneumaticcylinder having an extensible piston 667 secured to the X-ray carriageupright member 627. Extension and retraction of the piston 667 isoperative to move the X-ray sub-carriage 620 along the guide rods 661,662.

The movement of the X-ray sub-carriage 660 along the guide rods 661, 662is referred to as the X-ray sub-carriage offset movement. As will beexplained in greater detail, the offset movement is used in conjunctionwith the inspection of small tires having a relatively small innerdiameter which requires that the oblong X-ray tube assembly 700 be movedoff center in order to be admitted to the tire torus.

A pair of limit switches 660S₁, 660S₂ is provided to sense when theX-ray sub-carriage 660 is at opposite ends of its range of travel alongthe guide rods 661, 662. The switches 660S₁, 660S₂ are supported on abracket 668 secured to the X-ray carriage upright member 627. An arm 669secured to the bracket 666 selectively engages one of the switches660S₁, 660S₂ when the X-ray sub-carriage 660 is at opposite ends of itsrange of travel. The switches 660S₁, 660S₂ are electrically connected bysuitable conductors (not shown) to the control console 1300 to provide astep variation in a signal voltage.

The mast assembly 665 includes an upper plate 670 secured between two ofthe horizontally extending members 663. A guide rod 671 depends from theplate 670 in parallel spaced relationship with a pair of column members672, 673. A pair of stops 674 are carried on the top plate 670. A pairof stops 675 are carried near the lower ends of the column members 672,673.

THE X-RAY SUB-SUB-CARRIAGE

Referring to FIG. 21, and X-ray sub-sub-carriage 680 is movably mountedon the X-ray sub-carriage 660. The sub-sub-carriage 680 includes amounting block 681 which is apertured to slidably receive the guide rod671. A bracket 682 depends from the mounting blocks 681 and carries anX-ray tube housing assembly 700. Four shock absorber units 684 arecarried on the X-ray sub-sub-carriage 780 to engage the stops 674, 675when the X-ray sub-sub-carriage 681 is at opposite ends of its travelalong the guide rods 671.

A pneumatic motor 680M is provided on the mast 665 to move the X-raysub-sub-carriage 680 up and down along the guide rods 671. The motor680M is a pneumatic cylinder having a piston 686 movable along thelength of a tubular housing 687. A cable 688 has opposite ends connectedto the piston 686. A pair of pulleys 689 are rotatably carried atopposite ends of the motor 680M. The cable 688 is reeved around thepulleys 689. The cable 688 connects with the block 681 to drivinglyconnect the X-ray sub-sub-carriage 680 with the motor 680M. When thepiston 686 is driven downwardly by compressed air supplied to the motor680M, the X-ray sub-sub-carriage 680 travels to its up or retractedposition where the upper shock absorbers 684 engage the stops 674. Whenthe piston 686 is driven upwardly by compressed air supplied to themotor 686, the X-ray sub-sub-carriage 680 descends to its extendedposition where the lower shock absorbers 684 engage the stops 675.

A pair of limit switches 680S1, 680S2 are provided to sense when theX-ray sub-sub-carriage 680 is at the upper and lower ends of its rangeof travel. The switches 680S1, 680S2 are supported on the stops 674,675, and are selectively engaged by one of the shock absorbers 684 whenthe X-ray sub-sub-carriage 680 is at the upper or lower ends of itsrange of travel. The switches 680S1, 680S2 are electrically connected bysuitable conductors (not shown) to the control console 1300 to provide astep variation in a DC signal voltage.

THE X-RAY TUBE ASSEMBLY 700

The X-ray tube assembly 700 is of the type described in the referencedTire Inspector Patent. In brief, the tube assembly has a housing 701 andan X-ray tube (not shown) which is rotatably carried in the housing 701.The housing 701 is apertured at 703 to emit X-radiation. The housing 701and the tube are rotatable to direct a beam of emitted X-radiationupwardly and downwardly through an arc of about 80 degrees above andbelow a zero degree or horizontal orientation.

A sprocket 705 is connected to the sleeve 701. A drive chain 706 isreeved around the sprocket 705 and around a sprocket 707. The sprocket707 and an additional sprocket 708 carried on a stub shaft 709. The stubshaft 709 is carried by the bracket 682.

A reversible drive motor 700M is provided to rotate the housing 701. Themotor 700M has an output shaft which carries a sprocket 710. A drivechain 711 is reeved around the sprockets 708 and 710, and around anidler sprocket 712. When the motor 700M rotates the sprocket 710 in onedirection, the housing 701 and the X-ray tube rotate upwardly. When themotor 700M rotates the sprocket 710 in the opposite drive direction, thehousing 701 and the X-ray tube rotate downwardly.

The orientation of the housing 701 and the X-ray tube is monitored by apotentiometer 700P. The potentiometer 700P is carried on the bracket 682and has a rotatable stem 713 which carries the sprocket 712. Rotation ofthe sprocket 712 by the motor 700M effects concurrent rotation of thepotentiometer stem 713. A suitable electrical cable (not shown) connectsthe potentiometer 700P with the control console 1300. The potentiometer700P provides a resistance which varies to provide a variation in asignal voltage indicating the direction of X-ray beam emission from theX-ray tube assembly 700.

THE X-RAY TUBE SHIELD 750

Referring to FIG. 21, an X-ray tube shield 750 is carried on the X-raysub-carriage 660. The shield 750 includes a cylindrical lead-lined steelmember 751 provided with a U-shaped recess 752 to receive the X-rayhousing 701. An arm 753 secured to a bracket 754 supports the member751. The bracket 754 is supported for movement relative to the columnmember 672 in directions indicated by the arrow 755. A pair of guiderods (not shown) are carried on the column member 672. The bracket 754journals these guide rods to movably mount the shield 750 on the X-raysub-carriage 660.

A pneumatic motor 750M is provided for moving the X-ray shield 750 inthe directions of the arrow 755. The motor 750M is an extensiblepneumatic cylinder having one end connected to the bracket 754. Theother end of the cylinder 750M is connected to a bracket 756 secured tothe column member 672. When the cylinder 750M extends, the shield 750Mis moved rightwardly as viewed in FIG. 21 to uncover the X-ray beamemission aperture 703 and permit the X-ray sub-sub-carriage 680 todescend to the extended position shown in FIG. 21. When the cylinder750M retracts with the X-ray sub-sub-carriage 680 in its up or retractedposition, the shield 750 moves leftwardly to cover the X-ray emissionaperture 703.

A pair of limit switches 750S₁, 750S₂ are provided to sense when theX-ray shield 750 is at the opposite ends of its range of travel. Theswitches 750S₁, 750S₂ are supported on the bracket 756 secured to thecolumn member 672. An arm 757 secured to the housing of the cylinder750M selectively engages one of the switches 750S₁, 750S₂ when the X-rayshield 750 is at the left or right ends of its range of travel. Theswitches 750S₁, 750S₂ are electrically connected by suitable conductors(not shown) to the control console 1300 to provide a step variation in asignal voltage.

THE TRAVELING POSITIONING SWITCH 820

Referring to FIG. 22 in connection with FIG. 1, a traveling positioningswitch assembly 820 is carried on the main frame 320 at a positionleftwardly of the X-ray sub-carriage 660. The main frame assembly 320has a bracket 328 which depends from the beam 326. A channel member 821is welded to the bottom end of the bracket 328. A pair of guide rods 822are carried on the channel 821 along the forward side of the channel821. A mounting block 823 is apertured to slidably receive the rods 822for sliding movement along the rods 822.

A drive motor 820M is carried on the channel 821 for moving the block823 along the guide rods 822. The motor 820M carries a drive sprocket(not shown) which drives a roller chain 824. The roller chain 824 isreeved around a sprocket 825 carried near one end of the channel 821. Abracket 826 secures the block 823 to the roller chain 824. When themotor 820M rotates the roller chain 824 in one direction, the block 823moves rightwardly along the guide rods 822. When the motor 820M rotatesthe chain 824 in the opposite direction, the block 823 moves leftwardlyalong the guide rods 822.

The position of the block 823 along the guide rods 822 is monitored by apotentiometer 820P. The potentiometer 820P is carried on a bracket 828secured to the channel 821. The potentiometer 820P has a stem 829 whichis secured to the sprocket 825. Rotation of the sprocket 825 by themotor 820M effects concurrent rotation of the potentiometer stem 829. Asuitable electrical cable (not shown) connects the potentiometer 820Pwith the console 1300. The potentiometer 320P provides a resistancewhich varies to provide a variation in a signal voltage indicating theposition of the block 823 along the guide rods 822.

A pair of limit switches 820S₁, 820S₂ are carried near opposite ends ofthe channel 821. An arm 827 secured to the block 823 selectively engagesone of the limit switches 820S₁, 320S₂ when the block 823 is at oppositeends of its range of travel along the guide rods 822. The switches820S₁, 820S₂ are electrically connected by suitable conductors (notshown) to the control console 1300 to provide a step variation in asignal voltage.

A shaft 830 is journaled by the block 823. Three depending arms 831,832, 833 have their upper end regions connected to the shaft 830. A longroller 834 extends between the arms 831, 832. A plurality of shorterrollers 835 extend between the arms 832, 833. A pair of counterweights836 connect with the shaft 830 to bias the arms 831, 832, 833rightwardly to the position shown in solid lines in FIG. 22.

A pair of limit switches 452S₁, 452S₂ are carried on the block 823. Apair of cams 837, 838 are secured to the shaft 830 for actuating thelimit switches 452₁, 452S₂. The limit switch 452S₁ is a "slow-downswitch". When a tire moving along the main conveyor rolls 452 engagesthe roller 834 and pivots the arms 831, 832, 833 leftwardly as viewed inFIG. 22, the cam 837 actuates the plunger of the slow-down switch 452S₁,to slow the speed at which the main conveyor 450 is being driven by themotor 452M. The limit switch 452S₂ is a "stop switch". When the arms831, 832, 833 are pivoted leftwardly to a greater extent than isrequired to trip the switch 452S1, the cam 838 actuates the plunger ofthe limit switch 452S2 to stop the driving action of the main conveyormotor 452M.

As will be explained, the position of the block 823 along the guide rods822 is pre-set in accordance with the size of a tire to be inspected. Bypre-setting the block 823 along the guide rods 822, the limit switchrollers 834, 835 are positioned to slow down and stop the conveyor 540and thereby position a tire to be inspected directly beneath the X-raytube sub-carriage 660. After a tire has been inspected the conveyor 450moves the tire leftwardly, pivoting the arms 831, 832, 833 leftwardlyout of the way of the tire as it is discharged from the shieldedenclosure 275.

THE INPUTS TO AND THE OUTPUTS FROM THE CONTROL CONSOLE 1300

Referring to FIGS. 23A, 23B the outputs from the several describedphotocells and limit switches are shown schematically as forming inputsto the control console 1300. Each of the inputs is shown as selectivelyforming a connection with a line conductor 1000. There are a total of 40of these inputs, numbered 1001-1040.

The output signal from the photocell 101P1 forms the input 1001. Theoutputs from the limit switches 140S1, 104S2 form the inputs 1002, 1003.The outputs from the photocells 142P1, 142P2 connected in parallel formsthe input 1004.

The outputs from the limit switches 160S1, 160S2 form the inputs 1005,1006. The outputs from the photocells 161P1, 161P2 connected in parallelforms the input 1007. The outputs from the limit switches 190S1, 190S2connected in series forms the input 1008.

The output signal from the limit switch 195S1 forms the input 1009. Theoutput from the normally closed contacts of the photocells 278P1, 278P2connected in series forms the input 1010. The output from the normallyclosed contacts of the limit switches 278S1 connected in series formsthe input 1011. The output from the normally closed contacts of thelimit switches 278S2 connected in series forms the input 1012.

The outputs from the switches 340S1, 340S2, 390S1, 390S2, 420S1, 420S2form the inputs 1013, 1014, 1015, 1016, 1017, 1018. The output from thenormally closed contacts of the switches 440S1, 440S2, 440S3 connectedin series with the normally closed contacts of the photocell 440P1 formsthe input 1019.

The outputs from the switches 451S1, 451S2, 452S1, 452S2, 456S1, 456S2,460S1, 460S2, 550S1, 550S2 form the inputs 1020, 1021, 1022, 1023, 1024,1025, 1026, 1027, 1028, 1029. The outputs from the normally closedcontacts of the photocells 600P1, 600P2, 600P3, 600P4 connected inseries forms the input 1030.

The output from the switches 620S1, 620S2, 660S1, 660S2, 680S1, 680S2,750S1, 750S2, 820S1, 820S2 form the inputs 1031, 1032, 1033, 1034, 1035,1036, 1037, 1038, 1039, 1040.

Referring to FIG. 24, the outputs from the several describedpotentiometers and tachometer are shown schematically as forming inputsto the control console 1300. Each of the potentiometers and tachometeris shown as selectively forming a variable resistance connection withthe line conductor 1000. There are a total of 13 of these inputs,numbered 1101-1113.

Referring to FIGS. 25A, 25B, the inputs to the several describedelectric motors, to several solenoid valves which operate the describedpneumatic motors and to the pressure regulator are shown schematicallyas forming outputs from the control console 1300. Each of the shownwindings of motors, solenoids and pressure regulator has one conductorconnected to a line conductor 1200. The other sides of these windingsare connected to a total of 44 console outputs, numbered 1201-1244.

The output 1201 connects to the motor 101M. The outputs 1202, 1203connect to forward and reverse windings of the motor 140M. The output1204 connects to the motor 142M. The outputs 1205, 1206 connect toforward and reverse windings of the motor 161M.

The outputs 1207, 1208 connect to the windings of two solenoid valves1207V, 1208V for selectively supplying pressurized air to opposite endsof the pneumatic motor 195M.

The outputs 1209, 1210 connect to the windings of two solenoid valves1209V, 1210V for selectively supplying pressurized air to opposite endsof the pneumatic motors 278M.

The outputs 1211, 1212; 1213, 1214; 1215, 1216; and 1217, 1218; connectto forward reverse windings of the motors 340M; 390M; 420M; and 450M,respectively.

The outputs 1219, 1220 connect to the windings of two solenoid valves1219V, 1220V for selectively supplying pressurized air to opposite endsof the pneumatic motors 451M.

The outputs 1221, 1222 connect to the windings of two solenoid valves1221V, 1222V for selectively supplying pressurized air to opposite endsof the pneumatic motors 456M.

The outputs 1223, 1224 and 1225, 1226 connect to forward and reversewindings of the motors 460M and 510M.

The outputs 1227, 1228 connect to the windings of two solenoid valves1227V, 1228V for selectively supplying pressurized air to opposite endsof the pneumatic motors 550M.

The outputs 1229, 1230 connect to high and low pressure windings of thepressure regulator 559 for selectively supplying the valves 1227V, 1228Vwith high or low pressure air.

The outputs 1231, 1232; 1233, 1234; 1239, 1240; and 1243, 1244 connectto forward and reverse windings of the motors 600M; 620M; 700M; and820M, respectively.

The outputs 1235, 1236; 1237, 1238; and 1241, 1242 connect to thewindings of solenoid valves 1235V, 1236V; 1237V, 1238V; and 1241V, 1242Vfor selectively supplying pressurized air to opposite ends of thepneumatic motors 660M; 680M; and 750M.

THE CONTROL CONSOLE 1300

Referring to FIG. 2, the console 1300 includes a power control panel1302, an inspection control panel 1304, and a fault indicator panel1306. The console 1300 also preferably houses an automatic controlapparatus for the tire inspector apparatus, as will be explained below.

The power control panel 1302 includes switches and circuit breakersconnected for governing the safe operation of the electrical componentsof the tire inspector apparatus. The power control panel 1302 alsoincludes metered controls 1312 for adjusting the current and voltagesupplied to the X-ray tube carried in the housing 702.

The inspection control panel 1304 includes a television screen 1314. Thetelevision screen 1314 is connected to the X-ray imaging unit 440 forprojecting an image of a tire being inspected onto the television screen1314 for viewing by an operator.

The inspection control panel 1304 also has functional control elements,including a series of control buttons 1316 connected for manuallycontrolling the scanning functions of the tire inspection apparatus, andfor selecting its mode of operation, as will be explained below. It alsoincludes a series of buttons 1317 connected for manually controllingvarious drive functions of the tire inspection apparatus 100 and thebelt conveyors 101, 102.

The inspection control panel 1304 also includes speed controls 1318 forcontrolling the speed of movement of the X-ray imaging unit 440 and ofthe tire rotation spindles 600.

The fault indication panel 1306 includes three dials 1319 connected formanually adjusting the tire inspection apparatus to accommodate tireshaving a prescribed inside diameter, outside diameter, and height. Italso includes a bead-spread multiplier adjuster 1320. A fault indicatordisplay including eight lights 1321 is provided for indicatingmalfunctions in the tire inspector apparatus.

THE CONTROL SYSTEM 1325

The control apparatus for the tire inspector apparatus preferablyincludes a computer 1310, which is mounted in the console 1300. Thecomputer 1310 monitors all functions of the tire inspector apparatus 100and actuates the control system to drive the tire inspector componentsin a predetermined manner to perform tire inspection.

The control system housed within the console 1300 is shown in block formin FIG. 26. The control system 1325 receives inputs 1001-1040 and1101-1113 from the several described sensing elements connected tovarious components of the tire inspector apparatus 100. The sensorinputs indicate conditions associated with the components to which theyare connected. The control system 1325 processes the sensor inputs andgenerates outputs 1201-1244 which actuate the various drive mechanismsof the tire inspector in accordance with the sensed conditions. Otheroutputs produced by the control apparatus actuate the fault indicationdisplay lamps 1321 to indicate certain malfunctions which may occurduring an inspection cycle.

The control apparatus, as shown in FIG. 26 includes input conditioningcircuitry and output conditioning circuitry. Interposed between theinput and the output conditioning circuitry is the computer 1310. Thecomputer 1310 operates upon the input signals 1001-1040 and 1101-1113according to its program, and generates signals which actuate the outputconditioning circuitry to produce the outputs 1201-1244 controlling thetire inspector.

The input conditioning circuitry includes a multiplexer 1330 and ananalog to digital converter 1332. The multiplexer receives the analoginputs in parallel and directs them serially to the analog to digitalconverter. The analog to digital converter produces and directs digitalsignals representing the analog inputs to the computer. The DC inputsfrom the limit switches and photocells are directed in parallel to alevel translator 1334. The level translator alters the level of the DCinputs to enhance their detactability and presents these signals to thecomputer.

The output conditioning circuitry includes an analog to digitalconverter 1336 and a level translator 1340. The analog to digitalconverter is connected to the computer to receive digital outputsrepresenting motor control signals. The digital to analog converterconverts these digital outputs to analog form. These analog motorcontrol outputs are then applied in parallel respectively to the variousmotors of the tire inspection apparatus to control them according to thecomputer program and the condition of the input signals. The leveltranslator receives output signals from the computer representing DCoutputs which are utilized in operation of the tire inspectionapparatus. The level translator alters the level of these outputs torender them suitable for presentation to the various elements of thetire inspection apparatus.

The multiplexer 1330 and analog to digital converter 1332 of the inputconditioning circuitry is a Computer Products Model 7460 High LevelAnalog Input System. The level translator 1334 is a pair of TexasInstruments No. 966495-32 Input Data Modules, in parallel, withoptically coupled isolation.

The digital to analog converter 1336 in the output conditioningcircuitry is a Computer Products Model 7430 Digital Output AnalogSystem. The level translator 1340 is a Texas Instruments No. 217380-32Output Data Module.

The computer 1310 is a Texas Instruments Model 960A, with a battery packto render its read-write memory nonvolatile, and a communicationregister unit output line expander kit. Timing for the computer isestablished by a Timer 1342. The timer 1342 is a Texas Instruments No.214114 Interval Timer connected to the computer.

A tape reader 1344 is connected to the computer 1310 for inputting theprogram to the computer. The program for the computer 1310 is written onpunched paper tape in a known fashion. The tape reader 1344 is suitablya Remex Model RR-6300BAX/66X High Speed Paper Tape Reader.

The fault indicator display lamps 1321 are connected to the computer1310 to receive signals which indicate the existence and nature ofmalfunctions in the tire inspection apparatus 100. The malfunctionindicative signals are generated when a predetermined circumstance orcombination of circumstances exist with respect to the tire inspectionapparatus which are dangerous, and/or potentially destructive to themachinery. The computer 1310 produces malfunction indicative signals inresponse to the input signals 1001-1040 and 1101-1113 received by thecomputer by the sensing devices. The program input to the computer bythe tape reader 1344 determines the prerequisites for production of suchmalfunction indicative signals, and the nature of those signals.

The fault indicator display lamps 1321 are illuminated in patternsaccoding to a code which enables identification of the nature of thedetected malfunction from the pattern.

Alternately, the fault indication display can be a print-out deviceconnected to the computer. In such an embodiment, the program input tothe computer by way of the tape reader conditions the computer toproduce signals which actuate the print-out device to write out directlylegible diagnostic messages to the operator indicating the nature of themalfunctions.

Preferably, a logging apparatus 1350 may be connected to the computer1310. The logging apparatus 1350 in useful in maintaining a permanentrecord of the history of the tire inspection operations performed by thetire inspection apparatus. It is also useful in transmitting datarelating to tire inspections to remote locations for recording and/orimmediate observation. Such logging apparatus suitably includesperipheral devices such as a printer machine, data modems, and magnetictape transport, the selection of which is withint the level of ordinaryskill.

The mechanical functions of the tire inspection apparatus 100 are allcapable of actuation independently of each other. Moreover, the controlapparatus drives and monitors all functions and combinations offunctions simultaneously. Therefore, the sequence of operations andfunctions is fully controllable by the program input to the controlapparatus, within the mechanical limitations of the tire inspectionapparatus. The operation can also be completely automatic.

The sequence of operations of the tire inspection apparatus isdetermined according to the nature of the particular program input tothe computer. It is therefore not necessary to make mechanicalalterations to the apparatus to alter the mode of its operation. Theonly down time required to alter the operational sequence is that whichis necessary to change the program, i.e., to remove one paper tape fromthe tape reader and substitute another.

Due to the nonvolatile nature of the computer memory, a power down,power failure or deliberate interruption of the automatic execution oftire inspections will not upset the operation of the tire inspectionapparatus. Upon return of power, ot termination of the programinterruption, the system resumes its automatic operation at the samepoint at which operation ceased due to the power cut-off orinterruption.

OPERATION

The control apparatus 1325 operates the tire inspection apparatus 100 inaccordance with an automatic mode as determined by the computer program.A flow chart setting forth the operative functions of a suitableautomatic operating mode of the tire inspection apparatus is shown inFIGS. 27A-27E. The flow chart also describes the functional commands ofa suitable program for executing the automatic mode.

To initiate operation of the inspection apparatus 100, a punched papertape representing a program is placed in the high speed tape reader1344. The program is run through the tape reader 1344 to input it to thecomputer 1310 thereby enabling the computer 1310 to operate the tireinspection apparatus 100 in accordance with the program.

The automatic mode proceeds in accord with the following steps:

1. The tire is delivered to the roller conveyor 140;

2. The arm assemblies 161 and width sensor bar 210 measure and centerthe tire;

3. The image unit 440, spindles 600, and their associated components areprepared for entry of the tire to the shielded enclosure 275;

4. The tire is delivered to the enclosure 275.

5. The imaging unit 440 and X-ray tube assembly 700 moves to aninspection position and the spindles 600 engage the tire;

6. The imaging unit 440, X-ray tube assembly 700 and spindles 600cooperate to produce images of the inspected regions of the tire;

7. The spindles 600 disengage the tire and the imaging unit 440 andX-ray tube assembly 700 withdraw;

8. The tire is discharged from the enclosure 275 and a subsequent tireis admitted.

The first general operation of the automatic mode is to deliver tires tobe inspected one by one onto the centering table roller conveyor 140 fordimensional measurement and centering. Referring to FIG. 27A, the firststep in executing the program is for the control apparatus to generate amotor control signal to actuate the motor 101M to move a tire along thebelt conveyor 101 until it interrupts the light beam incident on thephotocell 101P₁. The control apparatus does this by monitoring theoutput of the photocell 101P₁, and generates a motor control signalactuating the motor 101M in response to the beam being incident on thatphotocell. The actuation of the motor 101M continues at least until theconveyor 101 delivers a tire to a point at which it interrupts the beamincident upon the photocell 101P₁.

If the following preconditions are fulfilled, the control apparatus 1325continues the actuation of the motor 101M to move the tire onto thecentering table 120, and actuates the motor 142M to advance the tire onthe centering table:

1. The photocells 142P₁ and 142P₂ produce signals indicating that thecentering table 120 is clear of objects;

2. The potentiometer 161P produces a signal to the control apparatusindicating that the arm assemblies 161 are open to at least apredetermined extent to receive a tire between them;

3. The potentiometer 195P produces a signal to the control apparatusindicating that the width sensor bar 210 is raised to a predeterminedextent to receive a tire;

4. The limit switches 190S₁ and 190S₂ do not indicate contact by the armassemblies 161 with an object;

5. The limit switch 195S produces a signal indicating the width sensorbar is not engaging an object;

If any of these preconditions are not fulfilled, the control apparatus,upon the advance of a tire to photocell 101P, deactuates the motor 101Mand will not actuate the motor 142M until all the preconditions aresatisfied.

If these preconditions are met, the tire is moved along the centeringtable roller conveyor 140 until it interrupts the light beam on one ofthe photocells 142P₁ and 142P₂. Such an interruption indicates to thecontrol apparatus 1325 that the tire has arrived at a predeterminedpoint called a "centering station" on the centering table conveyor 140.When a tire is in the centering station the arm assemblies 161 and widthsensor bar 210 can engage the tire to measure and center it. At thispoint, the control apparatus produces a motor control signal todeactuate the motor 142M to stop the rotation of the centering tableconveyor rolls 142.

Assuming that the preconditions are satisfied, and the tire is advancedonto the roller conveyor 140, the control system 1325 actuates the motor101M to continue running and to advance a subsequent tire along the beltconveyor 101. The belt conveyor 101 continues to run until the photocell101P₁ detects the arrival of the subsequent tire at the end of the beltconveyor 101. The control apparatus 1325 then produces a motor controlsignal deactuating the motor 101M.

The motor 101M remains deactuated until later in the automatic mode, atwhich time it is reactuated, as will be explained below.

When the tire has arrived at the centering station the control apparatus1325 produces control signals to first move the centering arms 161inwardly to measure the outside diameter and to center the tire. The armassemblies 161 are moved inwardly toward the tire in response to theinterruption by the tire of the light beam of the photocells 142P₁,142P₂. The control apparatus does this by producing a motor controlsignal actuating the motor 161M to move the arm assemblies 161 towardthe tire. When both arm assemblies 161 contact the tire, the switches190S₁ and 190S₂ provide DC output signals to the control apparatus, inresponse to which the control apparatus generates a motor control signalwhich stops the motor 161M. The potentiometer 161P is then producing ananalog signal representative of the outside diameter of the tire, whichsignal is transmitted to the control apparatus and its value stored forlater use.

The simultaneous inward motion of the arms 161 also centers the tire onthe roller conveyor 140. This is needed to assure that the tire, whenlater moved into the enclosure 275, will move along a feed path toposition its central axis for proper engagement by the spindles.

Upon actuation of the switches 190S₁ and 190S₂, the control apparatusalso actuates the motor 161M to move the arms 161 away from each other.

The control apparatus then produces a signal actuating the motor 190M tomove the width sensor bar downwardly. The width sensor bar continues tomove downwardly until it contacts the tire sidewall. At that point, theswitch 195S produces a signal to the control apparatus indicating suchcontact. In response to the signal from the switch 195S, the controlapparatus examines and stores a signal representing the signal producedby the potentiometer 195P, which represents the width of the tire afterthe switch 195S senses tire contact, the control apparatus actuates thepneumatic motor 195M to move the width sensor bar upwardly to the upperlimit of its range of travel.

When the arm assemblies 161 move apart to a predetermined degree, asindicated by the analog signal of the potentiometer 161P, the controlapparatus actuates the motor 278M to open the doors 278 of the shieldedenclosure 275. The control system also actuates the motor 161M to stopthe arms 161 after reaching the predetermined separation.

The control apparatus then moves the imaging unit 440 laterallyoutwardly to clear both the measured outside diameter of the tire andthe width of the main conveyor 450. The lateral position of the imagingunit 440 is monitored by the analog signals produced by thepotentiometers 340P and 420P, respectively. In response, the controlsystem produces motor control signals to actuate the motors 340M and420M to move the imaging system carriage 340 and imaging systemsub-sub-carriage 420 outwardly until the imaging unit 440 is laterallyoutside the measured tire outside diameter and the main conveyor frame451.

The control system actuates the pressure regulator 559 to set thespindle pressure as a predetermined function of the measured tire widthand outside diameter. This function establishes the proper spindlepressure according to the size, and therefore the weight, of the tire.

The control apparatus actuates the motor 820M to move the travelingpositioning switch assembly 820 to a position for engaging the tire whenthe tire has moved into the enclosure. The position is selected suchthat it is appropriate for engagement of the tire by the spindles, andfor subsequent inspection.

The X-ray tube sub-carriage 660 is then moved laterally if needed tolocate the X-ray tube assembly 700 within the maximum expected insidediameter of the tire when positioned for engagement by the spindles, atthe point established by the positioning switch assembly.

The control apparatus generates a signal representing the maximum insidetire diameter expected, as a predetermined function of the sensed tirewidth and outside diameter. The control apparatus monitors the lateralposition of the X-ray carriage by a signal produced by the potentiometer620P. The control system, in response to comparison of these values,produces a motor control signal to actuate the motor 620M to move theX-ray carriage 620 to locate the tube inside the maximum expected insidediameter of the tire.

The control apparatus 1325 compares the position of the imaging systemsub-carriage, as indicated by the signal generated by the potentiometer390P, with the value of that signal generated with the sub-carriagelocated in the central plane of the tire in its inspection position. Inresponse to this comparison, the control apparatus produces a motorcontrol signal to actuate the motor 390M to move the image systemsub-carriage to locate the imaging system at 0° with respect to thecentral plane of the tire to be inspected.

The control apparatus 1325 also senses the angle of emission ofX-radiation from the X-ray tube assembly 700 by the analog signalproduced by the potentiometer 700P. The control apparatus compares thatsignal with the corresponding value when the X-ray emission angle is atzero degrees, (horizontal) and produces a motor control analog signal toactuate the motor to pivot the X-ray tube to the zero degree position.

When the control system has sensed the imaging system 440 at the 0°position, it produces motor control signals to actuate the motor 460Mand the motor 140M to move the main conveyor gear racks 460 and pivotthe left end of the centering table roller conveyor 140 to assume amatching elevation which is a predetermined function of the tire widthsensed. The predetermined height is a function of the width of the tire,such that the mid-plane of each tire will enter the shielded enclosureat one predetermined level. Also, the motor 510M is actuated to causethe spindle carriages 510 to separate vertically. The purpose of thisstep is to position the centering table 120 and the main conveyor 450such that the tire moves smoothly onto the main conveyor from thecentering table. The purpose is also to simultaneously position the mainconveyor to place the incoming tire at an elevation appropriate formounting the tire on the spindles 600 for subsequent inspection.

The tire inspection apparatus then advances the tire into the enclosure275 for inspection.

The control apparatus senses whether the doors 278 are unobstructed asindicated by DC signals from the photocells 278P₁ and 278P₂. If thedoors 278 are unobstructed, the control apparatus, in response tofulfillment of the following additional preconditions, produces analogmotor control signals to actuate the motors 142M and 452M to move thetire from the roller conveyor 140 to the main conveyor:

1. The positioning switch assembly 820 is appropriately positioned as afunction of tire outside diameter;

2. Imaging system X-ray tube emission angle is set at 0° to the centralplane of the tire;

3. The main conveyor 450 and center table conveyor 120 are positioned ata level to receive the tire as specified above;

4. The spindles 600 are separated, as indicated by the potentiometer510P, by an amount which is a function of tire width, to clear the tire.

The control apparatus halts the tire when it has progressed along themain conveyor 450 to a predetermined position. The predeterminedposition is chosen as a position at which the tire is located formounting on the spindles 600 with its central axis along a predeterminedline in the inspection station.

The positioning switch assembly 820 provides signals to the controlapparatus causing it to stop the tire at the predetermined location.Those signals are generated in response to DC signals produced by thepositioning switch assembly 820.

The positioning switch assembly 820 depends from above the main conveyorand engages the tire as it moves along the main conveyor. When thepositioning switch assembly 820 engages the tire, the arms 831-833 pivotuntil the limit switch 452S₁ is actuated. This takes place when the tirereaches a location approaching the predetermined location. The limitswitch 452S₁ produces a signal to the control apparatus, in response towhich the control apparatus reduces the speed of the main conveyor 450,by a change in the signal actuating the motor 452M.

When the tire has advanced at this slower speed to the predeterminedlocation called the "inspection station", the arms 831-833 have pivotedto a position where the limit switch 452S₂ is actuated. The limit switchproduces a signal to the control apparatus, in response to which thecontrol apparatus produces a motor control signal deactuating the motor452M, stopping the tire at the predetermined position.

In response to the positioning switch assembly 820 indicating theadvancement of the tire to the inspection station, the control apparatusthen generates a motor control signal to actuate the motor 278M to closethe doors of the shielded enclosure 275. When the doors 278 are closed,a motor control signal is produced to actuate the motor 750M to uncoverthe X-ray tube.

The control apparatus 1325 then produces a signal to actuate the motor820M to move the positioning switch assembly to a removed position aboutfive inches forwardly of the leading edge of the tire, as sensed by thepotentiometer 820P.

Upon closure of the doors 278, any subsequent tire located at the end ofthe belt conveyor 101 is advanced onto the centering table 120 forcentering and measurement. The control apparatus, in response to thesignals from the switch 278S₂, actuates the motors 101M and 142M to movethe waiting subsequent tire onto the centering table. The subsequenttire is then centered and its outside diameter measured by the armassemblies 161. Its width is sensed by the width sensor assembly 195.

Meanwhile, the tire inspector apparatus moves the spindle carriages 510to insert the spindles 600 into the annulus of the tire which is to beinspected. This procedure is described in FIG. 27B of the flow chart.

The control apparatus 1325 then produces a motor control signal whichactuates the pneumatic motors 550M to move the spindle arms 550outwardly to engage the tire beads with the predetermined amount ofspindle pressure established by the setting of the pressure regulator559. The potentiometer 550P connected to the spindle arms 550 producesan analog signal indicating the degree of extension of the spindles 600when the extension stops, and consequently indicates the inside diameterof the tire. This signal is also directed to the control apparatus forstorage and later use.

The control apparatus then generates motor control signals to actuatethe motors 451M to lower the conveyor frame 451 a distance of about oneand one-half inches as indicated by the limit switch 4515₂. The controlapparatus also generates a motor control signal to actuate the motor456M to lower the main conveyor movable frames 456 to their lowermostposition, as indicated by conditions of the limit switches 456S₂ and456S₁.

The potentiometer 510P produces an analog signal to the controlapparatus which indicates the degree of separation of the upper andlower spindle carriages 710.

The motor 510M controls the degree of separation of the spindlecarriages 510. The control apparatus generates a motor control signalwhich actuates the motor 510M to separate the spindle carriages toaxially spread the beads of the tire supported on the spindles. Thedegree of desired bead separation is determined by the control system asa function of the tire width as sensed by the control apparatus, and ofthe operator setting on the beadspread multiplier switch 1320. Thedegree of beadspread is monitored by the potentiometer 510P.

The tire inspector apparatus 100 the maneuvers the X-ray tube assembly700 and imaging unit 440 to effect inspection of the tire.

The potentiometer 620P is connected to the X-ray carriage 620 andgenerates an analog input signal to the control apparatus 1325indicating the position of the X-ray carriage. The control apparatusactuates the motor 620M to move the X-ray carriage to position the X-raytube housing 701 over the tire annulus, within the inside diameter ofthe tire.

The control apparatus also generates an analog motor control signalwhich actuates the motor 340M to move the imaging system carriage 340 toa point at which the center of radius of the C-arms is at that pointwhere the X-ray tube focal point will be positioned for scanning.

The X-ray tube focal point is initially positioned as a function of theinside diameter of the tire. As will be more fully explained below, whena relatively large tire is to be inspected, the X-ray tube is preferablyinitially positioned for scanning with its focal point approximately ona cylinder defined by the inner edges of the tire beads. When a smalltire is to be inspected, the initial focal point position is at apredetermined point slightly inside that cylinder.

The initial tube focal point location is thus determined by the controlsystem as a function of the analog signals from the potentiometer 550P.The control system generates the analog signal to actuate the motor 620Mto move the X-ray tube carriage 620 to properly locate the tube focalpoint at the preferred initial position in response to this analoginput.

Preparatory manipulation of the tube for inspection proceeds. If thecontrol apparatus senses, by way of the limit switch 750S₂, that theX-ray tube is fully uncovered, the control apparatus produces a motorcontrol signal which actuates the motor 680M to move the X-raysub-subcarriage 680 to lower the tube.

After the X-ray tube housing assembly 700 is lowered into the tireannulus, the control apparatus under certain conditions generates amotor control signal to actuate the motor 660M to move the X-raysubcarriage 660 to geometrically offset the X-ray tube housing assemblyby 11/2 inches. The direction of this offset is parallel to the tirefeed path. The offsetting motion moves the focal point of the X-ray tubeto a position along a line perpendicular to the feed path and extendingthrough the central axis of the tire at the inspection station. Thisoffsetting motion is performed only in instances in which the tire hasan inside diameter of 13 inches or more.

FIGS. 21A through 21C illustrate the operation of the X-ray subcarriage660 in providing for the geometric offset. The size of the X-ray housingassembly 700 is such that it can barely be admitted to the annulus of atire with a 10-inch inside diameter, which is the inside diameter of thesmallest inspectable tire. The position which the X-ray tube housingassembly 700 must assume to permit its entry into a 10-inch insidediameter tire causes the tube focal point to be displaced from thecentral axis of the tire relative to the tire feed path.

If the tire inside diameter is sufficiently large, typically about 13inches or longer, the housing assembly 700 is offset by the X-raysubcarriage 660 to place the tube focal point along the lineperpendicular to the feed path and extending through the central axis ofthe tire.

If the tire inside diameter is smaller than 13 inches, the insidediameter of the tire will not accommodate the 1-1/2 inch offset movementof the housing assembly 700. Such movement would cause the housingassembly 700 to collide with the tire beads. In such instances, theoffset motion is not performed to avoid damage to the housing assembly700.

It is desirable to position the focal point of the X-ray tube betweenthe tire beads on a cylinder defined by the beads. For this purpose, theX-ray carriage 620 (partially illustrated in FIG. 21A by the elements627, 628) is moved, after offset, to position the focal point on thiscylinder. It is possible to position the focal point precisely on thiscylinder only in the case of tires having an inside diameter largeenough to accommodate geometric offset. The motion of the X-ray tubefocal point in the case of such a large tire is shown by the arrows inFIG. 21C. The horizontal arrow illustrates movement of the focal pointduring the offsetting step. The vertical arrow pointing downwardlyillustrates the further movement of the X-ray tube focal point outwardlyuntil it reaches the cylinder defined by the tire beads.

The motion of the focal point in the instance of small tires (insidediameter less than 13 inches) is shown in FIG. 21B. In this case, thereis no geometric offset, and the focal point is not moved to the linethrough the tire center axis. The only motion permitted for the focalpoint in this instance is motion imparted by the X-ray carriage 620toward the tire beads.

The actual scanning of the tire is then enabled if the control apparatus1325 determines that each of the following conditions is fulfilled:

1. The potentiometer 820P indicates that the positioning switch assembly820 is in its removed position, five inches forward the tire;

2. The X-ray tube assembly 700 is lowered, and offset, if possible asindicated by the input signals to the control system generated by thelimit switches 680S₂ and 660S₂, respectively;

3. The C-arms 380, 381 are positioned with their centers of radius alonga line through the focal point of the X-ray tube, as indicated by theanalog input signals to the control apparatus from the potentiometers340P and 620P; and

4. The main conveyor frame 451 and the movable frames 456 are lowered,as indicated by the DC input signals to the control apparatus from thelimit switches 460S₂, 460S₁, 456S₂ and 456S₁, respectively.

5. The imaging unit is located on the C-arms 380, 381 to 0° with respectto the central plane of the tire, as indicated by the analog output fromthe potentiometer 390P.

The control apparatus then establishes a "limited scheduled interrupt"scanning mode, which turns over to the operator for a time a number ofmanual tire inspection scanning functions. The operator can controlthese functions manually by depressing the various scanning functionbuttons 1316.

The functions of scanning which are turned over to manual operation bythe operator are the following:

1. Actuation of the motor 510M to control the spindle carriages 510 toadjust the beadspread of the tire;

2. Actuation of the motor 600M to rotate the tire in either direction byrotation of the spindles; the speed of this rotation can be controlledby the setting of the switch 1326a.

3. Actuation of the motors 340M, 390M, 420M, and 440M to control theposition and magnification of the imaging unit 440 to manipulate theimaging unit to form an image of the X-rays passing through the tire atany of a range of positions about the tire. Motion of the imaging systemsub-carriage 390 is speed controlled, by the setting of the switch1326b.

4. Actuation of the motors 620M, 660M, 680M, and 820M to control theX-ray tube pivot, and motion of the X-ray carriage 620, sub-carriage660, and sub-sub-carriage 680, to direct X-rays to desired portions ofthe rotating tire to facilitate inspection of the entire tire, or of anyselected part of it.

The control apparatus 1325, during the limited scheduled interruptscanning mode, synchronizes some of the movements of the X-ray tube andof the imaging unit. The control apparatus senses the pivotal positionof the X-ray housing 701 by the analog signal from the potentiometer700P, and produces a motor control signal to the motor 390M to move theimaging unit sub-carriage to move the imaging unit along the C-arms 380,381 to maintain its screen in the path of the X-rays emitted by thetube.

The control apparatus also maintains the imaging carriage C-arms withtheir centers of radius along a line through the X-ray tube focal point.This is done by sensing the position of the X-ray carriage asrepresented by the analog signal from the potentiometer 620P, and theC-arm position from the potentiometer 340P. The control system causesthe image system carriage to move the C-arms 380, 381 in response tochanges in position of the X-ray carriage 620 indicated by the signalfrom the potentiometer 620P. This feature maintains the magnification ofthe imaging system constant notwithstanding movement of the X-ray tube.

As more fully explained below, the control apparatus 1325 protects theapparatus and operator by refusing to respond to scanning buttoncommands which would execute potentially dangerous or destructivemovements.

X-rays emitted from the X-ray tube pass through portions of the tire andare received by the imaging unit. The imaging unit converts the patternof received X-radiation to video formated electrical signalsrepresenting an image of the tire portions, through which the X-rayshave passed. These electrical signals are directed to the televisionreceiver 1314, on the console 1300. The television receiver converts thesignals to a visual image of the tire portions showing certain featuresof internal tire construction, which may be viewed by the operator atthe console.

When the scanning of the tire has been completed to the satisfaction ofthe operator, the operator can depress a scanning function button on theinspection control panel 1304 which indicates the completion ofscanning, and produces an automatic mode resumption signal to thecontrol apparatus. The depression of this button actuates the controlapparatus 1325 to resume automatic operation of the tire inspectorapparatus. This subsequent automatic operation includes discharging theinspected tire from the shielded enclosure 275 and admitting asubsequent tire to the shielded enclosure for inspection.

When the operator depresses the automatic mode resumption buttonindicating the completion of inspection of the tire, the controlapparatus 1325 stops all motion of the tire inspector apparatus 100. Itdoes this by way of the analog motor control output signals.

The control apparatus then produces analog motor control signals (FIG.26) to actuate the motors 340M and 420M to move the image systemcarriage 340 and image unit 440, respectively, to clear the tire outsidediameter and the main conveyor.

As explained above, the subsequent tire is received on the centeringtable roller conveyor during inspection of the first tire, where thesubsequent tire is centered and measured.

The motor 660M is actuated to move the X-ray sub-carriage to straightenoffset which may have been assumed by the X-ray tube assembly 700 duringinspection of the first tire. The control apparatus then produces amotor control signal to actuate the motor 620M to move the X-raycarriage 340 to place the X-ray tube assembly 700 housing to clear boththe inside diameter of the first tire and the maximum expected insidediameter of the subsequent tire, as determined by measurement of theoutside diameter and width of the subsequent tire.

The control apparatus then produces analog motor control signals toactuate the motors 700M and 390M to pivot the X-ray tube housing 701 to0° with respect to the central plane of the first tire, and cause theimage system sub-carriage 390 to move the imaging unit also to 0°. Thecontrol apparatus also generates a motor control signal to actuate themotor 510M to move the spindle carriages toward each other to furtherinsert the spindle 600 to reduce the beadspread of the first tire to 3.5inches, which insertion is not enough to damage the X-ray tube assembly700.

Provided that the analog input signal from the potentiometer 620Pindicates that the X-ray tube is within the first tire inside diameter,that the potentiometer 700P indicates the X-ray tube housing 701 ispivoted to 0° and that the potentiometer 390P indicates the imageassembly 440 is positioned at 0° with respect to the central plane ofthe tire, the control apparatus 1325 generates a motor control signalwhich actuates the motor 680M to move the X-ray sub-sub-carriage 680 toraise the X-ray tube assembly 700 out of the first tire.

When the limit switch 680S₂ indicates that the tube is fully raised, thecontrol apparatus generates analog motor control signals to actuate themotors 340M and 420M to move the image system carriage 340 and imagesystem sub-sub-carriage 420 to position the image system assembly toclear the outside diameters of both the first and subsequent tires(sensed by the signal from the potentiometer 161P to the controlapparatus), and the main conveyor.

The control apparatus then produces a motor control signal to actuatethe motor 510M to momentarily insert the spindles 600 to their leastseparated position. This operation is performed provided that the signalgenerated by the potentiometer 620P produces an analog input to thecontrol apparatus indicating that the X-ray tube is positioned to clearthe inside diameter of the first tire.

The control apparatus also produces an analog motor control outputsignal to actuate the motors 451M and 456M to raise the main conveyorframe 451 and the movable frames 456, respectively to the levels atwhich they were set to admit the first tire. This level, as explainedabove, is a function of the width of the first tire. The controlapparatus also generates a motor control signal which actuates the motor820M to close the shield over the X-ray tube.

The control apparatus then produces a motor control signal whichactuates the motor 278M to open the doors 278 of the shielded enclosure275.

The control apparatus then produces a motor control signal to actuatethe motor 550M to move the spindle arms 550 to fully retract thespindles, provided:

1. The spindles are moved to their least separated position, asindicated by the analog input to the control system from thepotentiometer 510P;

2. The X-ray tube is fully raised, as indicated by the DC input to thecontrol apparatus from actuation of the limit switch 680S₁ ;

3. The movable frame 456 is in its uppermost position, as indicated bythe DC inputs to the control apparatus from the limit switches 456S₁ and456S₂ ;

4. The main conveyor frame 451 is fully raised as indicated by thesignal to the control apparatus from the limit switch 451S₁.

The control apparatus then generates an analog signal directed to thepressure regulator 559 to establish the spindle pressure for thesubsequent tire, determined in accordance with the measured outsidediameter of the subsequent tire. The control system also generates amotor control signal which actuates the motor 510M to remove the spindlecarriages to their most separated positions, as indicated by thepotentiometer 510P.

If the width of the first tire exceeds that of the subsequent tire bymore than a predetermined amount, a first procedure is followed toremove the first tire from the enclosure before admitting the subsequenttire. If the width of the first tire does not exceed that of thesubsequent tire by the predetermined amount, a second procedure isfollowed.

The first procedure is necessary when the first tire is substantiallywider than the subsequent tire. The main conveyor is elevated duringadmission of each tire to put the mid-plane of each tire at apredetermined level. This level is one which enables the mounting of thetire on the spindles for inspection.

If the first tire has substantially greater width than the subsequenttire, the mproper main conveyor level for the subsequent tire isinappropriate for admission of the subsequent tire. The larger tire, ifexited at the level set for the smaller tire, will run afoul of thedoors 278 of the shielded enclosure 275 or other parts of the tireinspector apparatus.

The first procedure, as described in FIG. 27D, includes the generationof a motor control signal to actuate the motor 450M to drive the mainconveyor 450 to move the first tire out of the shielded enclosure andonto the belt conveyor 102, which carries it away for further attention.This operation is enabled contingent upon indicating that the doors tothe shielded enclosure are open.

If there is no subsequent tire on the centering table, the controlapparatus 1325 actuates the motor 278M to close the doors 278 to theenclosure after exit of the first tire, as indicated by the signalproduced to the control apparatus by the photocell 278P₂.

If, however, a subsequent tire is located on the centering table 120,the control apparatus then produces motor control signals to actuate themotors 460M and 140M to reposition the main conveyor 450 and thecentering table 120 at the proper level for admitting the subsequenttire as determined by the width measurement of the subsequent tire. Thecontrol apparatus also generates a motor control signal to actuate themotor 550M to retract the spindles to assure they are in fact alreadyretracted. The control apparatus then actuates the motor to position theposition switch assembly 820 to stop the progress of the subsequent tirealong the main conveyor 450 at a point to enable its engagement with thespindles 600.

The control apparatus then generates motor control signals to actuatethe motors 452M and 142M to drive the main conveyor and the centeringtable roller conveyor to move the subsequent tire from the centeringtable 120 into the shielded enclosure 275 on the main conveyor.

The operation of the tire inspection apparatus 100 then returns to thepoint indicated as K in portion of the flow chart of FIG. 27B, andproceeds therefrom in the fashion as explained above.

A second procedure for exiting the first tire is executed if the firsttire width does not exceed that of the subsequent tire by thepredetermined amount, so that the main conveyor 450 may be positioned tosimultaneously exit the first tire and admit the subsequent tire.

In the second procedure, the control apparatus 1325 generates motorcontrol signals to actuate the motors 450M and 142M to drive the mainconveyor and the centering table roller conveyor to simultaneously exitthe first tire and enter the subsequent tire, if the followingpreconditions are met:

1. The switches 278S₁ indicate that the doors are open;

2. The potentiometer 820P indicates that the positioning switch assembly820 is positioned as a function of the outside diameter of thesubsequent tire;

3. The potentiometer 510P indicates the spindles 600 are separated toclear the subsequent tire;

4. The potentiometers 340P and 420P indicate that the image systemcarriage 340 and sub-sub-carriage 420 are respectively positioned toenable the image unit to clear the outside diameters of the first andsubsequent tires and the outer boundary of the main conveyor.

The control apparatus 1325 then generates motor control signals toactuate the motors 460M and 140M to move the main conveyor 450 andcentering table roller conveyor, 140, respectively, to a position which,determined in accordance with the measured width of the subsequent tire,positions the subsequent tire at a level for engaging the spindles forsubsequent inspection. The procedure then resumes at point L on FIG. 27Bof the described flow chart.

INTERRUPT MODE

The machine operator, by depressing a button 1304a on the inspectioncontrol panel, can suspend the automatic mode of operation of theapparatus 100, as described above, and go instead to a manual orinterrupt mode of operation. In the interrupt mode, the operator mayactuate the apparatus 100 manually to perform a number of functions, bydepressing appropriate buttons 1320 on the panel 1304.

The operator can initiate operation in accordance with the interruptmode by pressing the interrupt button 1304a on the inspection controlpanel 1304 either while the tire is being scanned, or at a point in theprogram during which the tire is not being scanned.

If the interrupt mode is initiated during a period in which the tire isnot being scanned, the control apparatus enables the operator to actuateseveral of the components of the apparatus 100 according to a firstinterrupt procedure. The permitted functions are directed to (1) movingthe tire inspector components to prepare for entry of a tire, and (2)entering and engaging the tire for inspection.

According to the interrupt procedure the operator can manually actuatethe control apparatus to perform the following preparatory functions:

1. Produce a motor control signal which actuates the motor 620M to movethe X-ray carriage 620 to move the tube assembly 700 laterally withrespect to the tire feed path;

2. Produce motor actuation signals to actuate the motors 340M and 420Mto move the imaging unit carriage 340 and sub-sub-carriage 420outwardly, respectively, away from the main frame;

3. Produce a motor control signal to actuate the motor 390M to move theimaging system sub-carriage to move the imaging unit along the C-arms380, 381;

4. Produce a motor control signal to actuate the motor 660M to move theX-ray sub-carriage 660 in a direction to eliminate the offset of theX-ray tube by moving the tube parallel to the direction of tire feedmovement along the main conveyor;

5. Produce a motor control signal to actuate the motor 680M to move theX-ray sub-sub-carriage 680 to raise the X-ray tube assembly 700 towardits fully raised position;

6. Produce a motor control signal which actuates the motor 550M to movethe spindle arms 550 to retract the spindles to their fully retractedpositions;

7. Produce a motor control signal which actuates the motor 510M toseparate the upper and lower spindle carriages.

Having initiated the interrupt mode at a time when the tire is not beingscanned, the control apparatus 1325 permits the operator to perform theabove functions (1-7) in the order designated, but in no other order. Toexecute any of these functions, all the preceding functions must havealready been performed, either in the interrupt mode, or previouslyduring automatic operation. The operator cannot reverse the sequence ofthe above steps.

If the seven preparatory functions are executed by the operator in theinterrupt mode, or by the inspector apparatus in the automatic mode, anumber of other functions are then enabled, in interrupt mode. Theseinclude the manual initiation of motor control signals by the controlapparatus 1325 to perform the following functions, relating to entry andengagement of the tire for inspection:

8. Actuating the motor 142M to operate the centering table rollerconveyor, 140, or to stop such operation;

9. Actuating the motor 161M to operate the centering arms 161 in eitherdirection;

10. Actuating the motor 190M to move the tire width sensor bar in anupward or downward direction;

11. Actuating the motor 456M to move the movable frames 456 in an upwarddirecton only;

12. Actuating the motor 460M to change the height of the main conveyorgear racks;

13. Actuating the motor 140M to pivot the centering table rollerconveyor 140 up or down;

14. Actuating the motor 452M to operate or stop the driving of therollers of the main conveyor 450;

15. Actuating the motor 451M to move the main conveyor frame 451 in anupward direction;

16. Actuating the motor 750M to move the X-ray tube shield 750 to coverthe tube;

17. Actuating the motor 278M to open and close the doors 278, openingbeing permitted only if the X-ray tube is covered.

Once the enclosure is prepared to receive a tire and a tire issubsequently entered manually in the interrupt mode, the operator maythen manually execute several additional scanning preparatory steps.These scanning preparatory steps comprise causing the control apparatusto generate motor control signals which:

1. Actuate the motor 510M to move the spindle carriages to move theupper and lower spindles to within a predetermined distance of oneanother;

2. Actuate the motor 550M to extend the spindles;

3. Actuate the motor 460M to move the main conveyor 450 downwardly;

4. Actuate the motor 456M to move the movable frames 456 downwardly;

5. Actuate the motor 750M to move the X-ray tube shield to uncover thetube;

6. Actuate the motor 680M to move the X-ray sub-sub-carriage 680 tolower the X-ray tube.

The scanning preparatory steps 1-6 can only be performed in the orderindicated. This is dictated by the program of the control apparatus.

Each of the scanning preparatory steps 1-6 has a reciprocal step. Forexample, step 1 for moving the spindles together has a reciprocal stepof separating the spindles. Step 2 of extending the spindles has areciprocal step of retracting the spindles, and so on. The operator,upon reaching an intermediate point in the performance of the scanningpreparatory steps, rather than electing to complete the series ofscanning preparatory steps, may proceed in another manner. He mayperform the reciprocal of each of the scanning preparatory steps he hascompleted, in the reverse order in which the corresponding scanningpreparatory steps were performed. For example, if the operator hasproceeded through the first four steps, wherein the spindles are movedtogether, the main conveyor dropped, and the movable frames 456 lowered,he may proceed in reverse order with the reciprocal steps. That is, theoperator may then raise the movable frames 456, raise the main conveyor,retract the spindles, and separate the spindles.

If the operator initiates the interrupt mode while the tire is beingscanned in accordance with the automatic mode, then the operator therebyacquires control over the scanning functions of the apparatus 100 asexplained above in connection with the automatic mode. That is, theoperator can manipulate the X-ray tube carriage 620, sub-carriage 660and sub-sub-carriage 680, along with the imaging system carriage 340,sub-carriage 390 and sub-sub-carriage 420; he can control the speed anddirection of rotation of the tire by the spindles 600, and the degree ofinsertion of the spindles, in order to vary the beadspread as desiredfor effective inspection.

The operator, while proceeding in the interrupt mode, may return theapparatus 100 to automatic mode. This, however, is permitted only (1)during the time when a tire is actually engaged on the spindles, and (2)immediately upon exiting a tire.

There are two basic types of motors in the apparatus 100. One type isthe pneumatic motor, and the other is the drive motor assembly.

The pneumatic motors exert forces tending to move their associatedcomponents between two positions. As such, the motor control signals tothese motors need be only DC signals produced by the control apparatus.Each motor tends to move toward one position for one state of its DCmotor control signal, and assumes the other in response to the motorcontrol signal having another state.

The drive motors can assume any of a range of positions between twolimiting positions. The rotative position assumed by the drive motordepends on the value of an analog motor control drive signal directed tothat motor from the control apparatus and the time during which it isapplied. Each drive motor associated with a potentiometer causes thatpotentiometer to produce and direct to the control apparatus an analogsignal indicating the instantaneous positional state assumed by thedrive motor and its associated component. Each of the drive motors isspeed controllable as a function of the value of its analog motorcontrol signal produced by the control apparatus.

The control apparatus 1325, in the course of causing the tire inspectionapparatus to execute its above described functions, generates analogsignals operative for as long as needed to move the movable componentsto commanded positions determined by the control apparatus.

The control system 1325 provides for automatic slow down of the movablecomponents driven along paths of travel by drive motors associated withpotentiometers. The slowing of each component occurs when the componentapproaches to within a predetermined distance of:

1. an extreme of its travel path, or

2. its commanded position.

The control apparatus determines this approach by the analog signalsfrom the potentiometers associated with the respective components. Whenthe control system detects through a potentiometer that a movablecomponent approaches its extreme travel limit or commanded positionwithin a predetermined distance, the control system reduces the drivevoltage produced by the analog motor control signal, slowing down thecomponent.

MALFUNCTION DIAGNOSIS

The control apparatus for the tire inspector apparatus 100 senses theoccurrence of malfunctions of its components. The apparatus 100indicates the occurrence of these malfunctions on the malfunctionindication display 1306 on the control console 1300.

The malfunction indication display 1306 preferably includes a series ofeight lamps connected to the control apparatus. The control apparatus,upon sensing the occurrence of a malfunction, generates output signalswhich light one or more of the lamps. The lamps are lighted inaccordance with a code, which identifies the nature of the malfunction.

Whenever a malfunction is detected, the control apparatus producessignals which deactuate all the components of the tire inspectionapparatus, and turn over actuation of the apparatus 100 to the interruptmode, described above.

Preferably, the control apparatus actuates the lamps to light in aunique pattern according to a hexidecimal code to identify the nature ofeach different malfunction sensed by the control apparatus. In thepreferred embodiment, there are 105 different malfunctions which areidentified by the coded pattern of lighting of the malfunction displaylamps.

These malfunctions are listed below in tabular form in Table I. Table Ihas four columns. The data in column I indicates each malfunction whichcan be indicated, in conventional decimal form. The data in column IIindicates each type of malfunction in hexidecimal form.

The data in column III of Table I represents the pattern of lighting ofthe eight malfunction display lamps associated with each type ofmalfunction. In column III, a O represents an unlighted lamp in theposition on the malfunction indication display 1306 corresponding to theposition of the O in column III. The letter L represents the lighting ofthe malfunction display lamp located in the position on the malfunctiondisplay corresponding to the position of the L in column III.

                                      TABLE I                                     __________________________________________________________________________    I    II III          IV                                                       __________________________________________________________________________    0    00 0000 0000                                                                            No malfunction display lamps are lighted                                      when the tire inspector apparatus 100 is                                      operating without malfunction.                                 1    01 0000 000L                                                                            The photocells 141P1 and 141P2 direct                                         signals to the control apparatus follow-                                      ing actuation of the motors 142M and 101M,                                    indicating either that an obstruction is                                      on the entering table 120 or that the                                         photocells 142P1 and 142P2 are not both                                       operating properly.                                            2    02 0000 00L0                                                                            The photocells 161P1 and 161P2 are dark,                                      after the photocells 142P1 and 142P2 are                                      dark, indicating the presence of an                                           obstruction on the centering table 120,                                       malfunction of the centering table roller                                     conveyor 140, or of the belt conveyor 101,                                    or that the photocells 161P1 and 161P2                                        are not both operating properly.                               3    03 0000 00LL                                                                            The potentiometer 195P has failed to                                          indicate, after actuation of the motor                                        190M, that the width sensor bar 210 has                                       retracted to a predetermined location.                         4    04 0000 0L00                                                                            Either of the switches 161S.sub.1 and 161S.sub.2                              is actuated, producing a signal to the                                        control apparatus indicating that the                                         arm assemblies 161 have moved beyond                                          their permitted range of travel.                               5    05 0000 0L0L                                                                            The photocells 142P.sub.1 and 142P.sub.2 fail to                              indicate the positioning of a tire on                                         the centering table within a predetermined                                    time following the indication by the                                          photocell 101P.sub.1 that a tire has cleared                                  the belt conveyor 101. This could                                             indicate failure of the conveyor 101,                                         the centering table conveyor 140, or                                          malfunction of any of the photocells                                          101P.sub.1, 142P.sub.1, and 142P.sub.2.                        6    06 0000 0LL0                                                                            The photocell 101P.sub.1 remains dark after                                   one of the photocells 142P.sub.1 and 142P.sub.2                               becomes dark.                                                  7    07 0000 0LLL                                                                            The photocells 161P.sub.1 and 161P.sub.2 directly                             signal to the control apparatus indicating                                    that at least one of them remains dark                                        for a predetermined time after actuation                                      of the motor 142M. This indicates                                             malfunction of the roller conveyor 140,                                       or of either of the photocells 161P.sub.1                                     and 161P.sub.2.                                                8    08 0000 L000                                                                            The switch 190S.sub.1 and 190S.sub.2 produce a                                signal to the control apparatus indicating                                    that they remain in contact with an object                                    for greater than a predetermined length                                       of time, or are malfunctioning.                                9    09 0000 L00L                                                                            The switch 161S.sub.1, indicates that the                                     assemblies 161 have moved to their inner                                      extremities without contacting a tire,                                        indicating the tire has an outside diameter                                   too small for the apparatus 100 to handle.                     10   0A 0000 L0L0                                                                            The photocells 161P.sub.1 and 161P.sub. 2 produce                             a signal to the control apparatus                                             indicating that one of them remains dark                                      following the centering of a tire and                                         contact of the switches 190S.sub.1 and 190S.sub.2.                            This indicates that an excessively large                                      object is on the centering table 120, or                                      more than one tire is present on the                                          centering table.                                               11   0B 0000 L0LL                                                                            The switch 195S.sub.1 produces a signal to                                    the control apparatus indicating that                                         it is in contact with an object before                                        lowering, or is malfunctioning.                                12   0C 0000 LL00                                                                            The potentiometer 195P and the switch                                         195S.sub.1 produce signals to the control                                     apparatus indicating that the width sensor                                    bar 210 is not moving and is not in contact                                   with an object, following the actuation                                       of a motor 190M to move the width sensor                                      bar downwardly. This condition indicates                                      that the switch 195S.sub. 1 is defective, or                                  that the mechanism for moving the width                                       sensor bar has failed.                                         13   0D 0000 LL0L                                                                            The potentiometer 195P and the switch                                         195S.sub.1 produce signals to the control                                     apparatus indicating that the width sensor                                    bar has not retracted upwardly a pre-                                         determined distance within a predetermined                                    time after the switch 195S.sub.1 terminates                                   contact with a tire.                                           14   0E 0000 LLL0                                                                            One of the switches 278S.sub.2 produces a                                     signal to the control apparatus indicating                                    that the doors of the shielded enclosure                                      are not closed at a time in the operation-                                    al sequence when they should be, or that                                      one of the switches 278S.sub.2 is malfunction-                                ing.                                                           15   0F 0000 LLLL                                                                            One of the switches 278S.sub.1 produces a                                     signal to the control apparatus indicating                                    that it is made at a time in the operation-                                   al sequence when the doors should be                                          closed, indicating a malfunction of one                                       of the switches 278S.sub.1.                                    16   10 000L 0000                                                                            The photosensor 278P.sub.1 produces a signal                                  to the control apparatus indicating that                                      it is still receiving light, notwith-                                         standing that one of the switches 278S.sub.2                                  indicates that the front door is closed.                       17   11 000L 000L                                                                            The photosensor 278P.sub.2 produces a signal                                  to the control apparatus indicating that                                      it is receiving light notwithstanding                                         that one of the switches 278S.sub.2 indicates                                 that the rear door to the shielded                                            enclosure is closed.                                           18   12 000L 00L0                                                                            The switch 680S.sub.1 fails to produce a                                      signal to the control apparatus indicating                                    that the X-ray sub-sub-carriage has moved                                     the X-ray tube assembly 700 up at a time                                      in the operational sequence when it should                                    be up.                                                         19   13 000L 00LL                                                                            The switch 680S.sub.2 produces a signal indica-                               ting that it remains made at a time in the                                    operational sequence when the tube                                            assembly 700 should be raised, indicating                                     a malfunction of the switch 680S.sub.2.                        20   14 000L 0L00                                                                            The switch 451S.sub.1 fails to produce a                                      signal indicating that the frame 451 is                                       raised at a time in the operational                                           sequence when the frame 451 should be                                         raised.                                                        21   15 000L 0L0L                                                                            The switch 451S.sub.2 produces a signal to the                                control apparatus indicating that it is                                       made at a time in the operational sequence                                    when the frame 451 should be raised                                           indicating a malfunction of the switch                                        451S.sub.2.                                                    22   16 000L 0LL0                                                                            The switch 660S.sub.1 fails to produce a signal                               to the control apparatus indicating that                                      the X-ray sub-carriage has moved the                                          X-ray tube assembly 700 to a non-offset                                       position at a time in the operational                                         sequence when the X-ray tube assembly                                         should not be offset.                                          23   17 000L 0LLL                                                                            The switch 660S.sub.2 produces a signal to the                                control apparatus indicating that it is                                       made at a time in the operational                                             sequence when the X-ray tube should not                                       be offset, indicating a malfunction in                                        the switch 660S.sub.2.                                         24   18 000L L000                                                                            One of the switches 340S.sub.1 and 340S.sub.2                                 produces a signal to the control apparatus                                    indicating that the imaging system                                            carriage 340 has moved to an extreme                                          position of its range of travel.                               25   19 000L L00L                                                                            One of the switches 390S.sub.1 and 390S.sub.2                                 produces a signal to the control apparatus                                    indicating that the imaging system sub-                                       carriage 390 has reached an extreme                                           position of its path of travel.                                26   1A 000L L0L0                                                                            One of the switches 420S.sub.1 and 420S.sub.2                                 produces a signal to the control apparatus                                    indicating that the imaging system sub-                                       sub-carriage 420 has reached an extreme                                       of its path of travel.                                         27   1B 000L L0LL                                                                            One of the switches 440S.sub.1, 440S.sub.2, and                               440S.sub.3 and the photocell 440P.sub.1 produce a                             signal indicating to the control apparatus                                    that the imaging unit 440 has or is about                                     to contact another object.                                     28   1C 000L LL00                                                                            One of the switches 820S.sub.1 and 820S.sub.2                                 produces a signal to the control apparatus                                    indicating that the positioning switch                                        assembly 820 has reached an extreme of                                        its path of travel.                                            29   1D 000L LL0L                                                                            One of the switches 460S.sub.1 and 460S.sub.2                                 produces a signal to the control apparatus                                    indicating that the gear racks 460 have                                       reached an extreme of their path of                                           travel.                                                        30   1E 000L LLL0                                                                            One of the switches 140S.sub.1 and 140S.sub.2                                 produces a signal to the control apparatus                                    indicating that the centering table roller                                    conveyor 140 has reached an extreme in its                                    path of travel.                                                31   1F 000L LLLL                                                                            One of the switches 456S.sub.1 fails to                                       produce a signal to the control apparatus                                     indicating that the movable frame 456 is                                      raised at a time in the operational                                           sequence when the movable frame 456 should                                    be raised.                                                     32   20 00L0 0000                                                                            One of the switches 456S.sub.2 produces a                                     signal to the control apparatus indicating                                    that it is made at a time in the opera-                                       tional sequence when the movable frame                                        456 should be raised, indicating a mal-                                       function of one of the switches 456S.sub.2.                    33   21 00L0 000L                                                                            The switch 750S.sub.1 fails to produce a                                      signal to the control apparatus indicating                                    that the X-ray tube shield is covering                                        the X-ray tube at a time in the operational                                   sequence when the X-ray tube should be                                        covered.                                                       34   22 00L0 00L0                                                                            The switch 750S.sub.2 produces a signal to                                    the control apparatus indicating that it                                      is made at a time in the operational                                          sequence when the X-ray tube should be                                        covered, indicating a malfunction of the                                      switch 750S.sub.2.                                             35   23 00L0 00LL                                                                            One or more of the photocells 600P.sub.1                                      produces a signal to the control apparatus                                    indicating that it is not receiving light                                     just before the doors 278 open to admit                                       the tire, indicating a malfunctioning                                         photocell 600P.sub.1, or an object in the                                     enclosure.                                                     36   24 00L0 0L00                                                                            The switch 550S.sub.2 produces a signal to the                                control apparatus indicating that it is                                       made at a time in the operational sequence                                    when the spindles should be retracted,                                        indicating a malfunction in the switch                                        550S.sub.2.                                                    37   25 00L0 0L0L                                                                            The switch 550S.sub.1 fails to produce a                                      signal to the control apparatus indicating                                    that the spindles are retracted at a time                                     in the operational sequence when the                                          spindles should be retracted.                                  38   26 00L0 0LL0                                                                            One of the switches 278S.sub.1 fails to indicate                              that the shielded enclosure doors are                                         open within a predetermined time following                                    the actuation of the motor 278M to open                                       the doors.                                                     39   27 00L0 0LLL                                                                            One of the switches 278S.sub.2 indicates that                                 it is made at a time in the operational                                       sequence when the doors should be open,                                       indicating a malfunction in one of the                                        switches 278S.sub.2.                                           40   28 00L0 L000                                                                            The photocell 278P.sub.1 produces a signal to                                 the control apparatus indicating it is                                        not receiving light during a time in                                          which the switches 278S.sub.1 indicate that                                   the shielded enclosure doors are open.                                        This indicates an obstruction in the                                          front door, or failure of the photocell                                       278P.sub.1.                                                    41   29 00L0 L00L                                                                            The photocell 278P.sub.2 indicates to the                                     control apparatus that it is not receiving                                    light at a time when the switches 278S.sub.1                                  indicate that the shielded enclosure                                          doors are open. This indicates failure                                        of the photocell 278P.sub.2, or an obstruction                                in the rear door.                                              42   2A 00L0 L0L0                                                                            The switch 452S.sub.1 on the positioning switch                               assembly produces a signal to the control                                     apparatus indicating that it is made                                          prior to entry of the tire to the enclosure.                   43   2B 00L0 L0LL                                                                            The switch 452S.sub.2 of the positioning switch                               assembly 820 produces a signal to the                                         control apparatus indicating that it is                                       made prior to tire entry to the enclosure.                     44   2C 00L0 LL00                                                                            The switch 452S.sub.1 fails to produce a signal                               to the control apparatus within a pre-                                        determined time following actuation of                                        the main conveyor 450 to move the tire                                        to engage the limit switch assembly.                           45   2D 00L0 LL0L                                                                            The switch 452S.sub.1 fails to produce a signal                               to the control apparatus, before making                                       of the switch 452S.sub.2.                                      46   2E 00L0 LLL0                                                                            The switch 452S.sub.2 fails to produce a signal                               to the control apparatus within a pre-                                        determined time of the actuation of the                                       switch 452S.sub.1.                                             47   2F 00L0 LLLL                                                                            At least one of the photocells 600P.sub.1                                     produces a signal to the control apparatus                                    indicating that it is receiving light                                         during the entire period of tire entry                                        into the enclosure.                                            48   30 00LL 0000                                                                            The photocell 278P.sub.1 produces a signal                                    to the control apparatus indicating that                                      it fails to receive light for longer than                                     a predetermined period of time during which                                   the switches 278S.sub.1 indicate that the                                     shielded enclosure doors 278 are open.                                        This indicates an obstruction at the                                          front door.                                                    49   31 00LL 000L                                                                            The photocell 278P.sub.2 produces a signal to                                 the control apparatus indicating that it                                      fails to receive light for longer than a                                      predetermined period of time during which                                     the switches 278S.sub.1 indicate that the                                     shielded enclosure doors 278 are open.                                        This indicates an obstruction at the                                          rear door.                                                     50   32 00LL 00L0                                                                            The switch 278S.sub.2 fails to produce a                                      signal to the control apparatus indicating                                    the closure of the doors within a pre-                                        determined time following the actuation                                       of the motor 278M to close the doors 278.                      51   33 00LL 00LL                                                                            The switch 750S.sub.1 produces a signal to the                                control apparatus indicating that it is                                       made at a time in the operational sequence                                    when the X-ray tube should be uncovered,                                      indicating a malfunction of the switch                                        750S.sub.1.                                                    52   34 00LL 0L00                                                                            The switch 750S.sub.2 fails to produce a                                      signal to the control apparatus, indicating                                   that the X-ray tube shield has uncovered                                      the X-ray tube within a predetermined                                         time following actuation of the motor                                         750M.                                                          53   35 00LL 0L0L                                                                            The switch 452S.sub.1 produces a signal to the                                control apparatus indicating the engage-                                      ment of the positioning switch assembly                                       820 with a tire after the positioning                                         switch assembly should have backed away                                       from the tire.                                                 54   36 00LL 0LL0                                                                            The switch 452S.sub.2 produces a signal to                                    the control apparatus indicating the                                          engagement of the positioning switch                                          assembly with a tire at a time in the                                         operational sequence after the positioning                                    switch assembly should have backed away                                       from the tire.                                                 55   37 00LL 0LLL                                                                            The photocells 600P.sub.1 fail to produce                                     signals to the control apparatus indicating                                   that the tire is centered under the                                           spindles.                                                      56   38 00LL L000                                                                            The switch 550S.sub.1 produces a signal to                                    the control apparatus indicating that                                         the spindles are retracted for a pre-                                         determined period of time following the                                       actuation of the motor 550m to extend                                         the spindles.                                                  57   39 00LL L00L                                                                            The switch 456S.sub.2 fails to produce a                                      signal to the control apparatus indicating                                    that the movable frame 456 has reached                                        its lower position within a predetermined                                     time following the production of a signal                                     to the control apparatus by the switch                                        456S.sub.1 indicating that the movable frame                                  456 has moved from its raised position.                        58   3A 00LL L0L0                                                                            The switch 456S.sub.1 produces a signal indica-                               ting to the control apparatus that it is                                      made at a time in the operational sequence                                    when the movable frame should be in its                                       lowered position, indicating a malfunction                                    in the switch 456S.sub.1.                                      59   3B 00LL L0LL                                                                            The switch 451S.sub.2 fails to produce a signal                               to the control apparatus indicating that                                      the frame 451 has reached its lower                                           position, for a predetermined time follow-                                    ing the indication by the switch 451S.sub.1                                   to the control apparatus that the frame                                       451 has left its raised position.                              60   3C 00LL LL00                                                                            The switch 451S.sub.1 produces a signal                                       indicating that it is made at a time in                                       the operational sequence when the frame                                       451 should be in its lowered position,                                        indicating a malfunction of the switch                                        451S.sub.1.                                                    61   3D 00LL LL0L                                                                            The switch 680S.sub.2 fails to produce a                                      signal to the control apparatus indicating                                    that the X-ray sub-sub-carriage 680 has                                       lowered the X-ray tube assembly 700 within                                    a predetermined time following the                                            indication by the switch 680S.sub. 1 to the                                   control apparatus that the X-ray tube                                         assembly has moved from its raised position.                   62   3E 00LL LLL0                                                                            The switch 680S.sub.1 produces a signal to the                                control apparatus indicating that it is                                       made at a time in the operational sequence                                    when the X-ray tube assembly 700 should be                                    in a lowered position, indicating a mal-                                      function in the switch 680S.sub.1.                             63   3F 00LL LLLL                                                                            The switch 660S.sub.1 fails to produce a signal                               to the control apparatus indicating that                                      the X-ray sub-carriage has offset the                                         X-ray tube assembly 700 within a pre-                                         determined amount of time following the                                       indicating by the switch 660S.sub.2 to the                                    control apparatus that the X-ray tube                                         assembly has been moved from its non-                                         offset position.                                               64   40 0L00 0000                                                                            The switch 660S.sub.2 produces a signal to                                    the control apparatus indicating that                                         it is made at a time in the operational                                       sequence when the X-ray tube assembly                                         should be offset, indicating a malfunction                                    of the switch 660S.sub.2.                                      65   41 0L00 000L                                                                            The switch 660S.sub.2 fails to produce a                                      signal indicating that the X-ray sub-                                         carriage 620 has moved the X-ray tube                                         assembly 700 to its nonoffset position                                        for a predetermined amount of time follow-                                    ing an indication by the switch 660S.sub.1                                    that the X-ray tube has been moved from                                       its offset position.                                           66   42 0L00 00L0                                                                            The switch 680S.sub.1 fails to produce a signal                               to the control apparatus indicating that                                      the X-ray sub-sub-carriage 680 has raised                                     the X-ray tube assembly 700 within a pre-                                     determined period following the indication                                    by the switch 680S.sub.2 that the X-ray tube                                  has been raised from a lowered position.                       67   43 0L00 00LL                                                                            The switch 750S.sub.1 fails to produce a signal                               to the control apparatus indicating that                                      the X-ray tube shield 750 has been moved                                      to its covered position within a predeter-                                    mined time following the indication by the                                    switch 750S.sub.2 to the control apparatus that                               the X-ray tube shield has been moved from                                     its uncovered position.                                        68   44 0L00 0L00                                                                            The switch 451S.sub.1 fails to produce a signal                               indicating to the control apparatus that                                      the frame 451 has been raised to its upper                                    position within a predetermined time follow-                                  ing the production of a signal to the                                         control apparatus by the switch 451S.sub.2                                    indicating that the frame 451 has been                                        raised from its lowered position.                              69   45 0L00 0L0L                                                                            The switch 456S.sub.1 fails to produce a                                      signal to the control apparatus indicating                                    that the movable frame 456 has reached its                                    raised position within a predetermined                                        time after the switch 456S.sub.2 has indicated                                to the control apparatus that the movable                                     frame 456 has begun to be raised from                                         its lowered position.                                          70   46 0L00 0LL0                                                                            The switch 550S.sub.1 fails to produce a signal                               to the control apparatus indicating that                                      the spindles have retracted within a                                          predetermined time after the actuation                                        of the motor 550M to retract the spindles.                     71   47 0L00 0LLL                                                                            The photocell 278P.sub.2 fails to indicate to                                 the control apparatus that the tire has                                       interrupted the light beam falling on the                                     photocell within a predetermined time                                         following the actuation of the motor 450M                                     to exit the tire through the exit door.                        72   48 0L00 L000                                                                            The photocell 278P.sub.2 produces a signal to                                 the control apparatus indicating that the                                     light incident on the photocell 278P.sub.2 has                                been interrupted for more than a predeter-                                    mined time, during actuation of the main                                      conveyor 450M, indicating that the tire                                       is moving out too slowly.                                      73   49 0L00 L00L                                                                            The photocell 278P.sub.2 produces a signal to                                 the control apparatus indicating that a                                       tire is exiting, notwithstanding that                                         neither switches 820S.sub.1 nor 820S.sub.2 have been                          previously actuated by the tire's engage-                                     ment with the positioning switch assembly                                     820.                                                           74   4A 0L00 L0L0                                                                            The photocell 278P.sub.2 produces a signal to                                 the control apparatus indicating that the                                     tire has exited while one of the switches                                     820S.sub.1 and 820S.sub.2 produce a signal indicating                         engagement of the positioning switch                                          assembly 820 by a tire.                                        75   4B 0L00 L0LL                                                                            The control apparatus detects a power                                         failure in the control apparatus, via a                                       connection from the power control panel                                       1302.                                                          76   4C 0L00 LL00                                                                            The control apparatus detects a memory                                        parity error in the memory of the computer                                    which requires service. This is detected                                      by a connection to a built-in terminal on                                     the computer 1310.                                             77   4D 0L00 LL0L                                                                            The control apparatus detects an                                              unrecognized code in input to the control                                     apparatus, via a built-in terminal on the                                     computer 1310.                                                 78   4E 0L00 LLL0                                                                            The control apparatus detects a memory                                        violation in the computer, which requires                                     service, via a built-in terminal on the                                       computer 1310.                                                 79   4F 0L00 LLLL                                                                            One of the switches 440S.sub.1, 440S.sub.2, 440S.sub.3                        or the photocell 440P.sub.1 produces a signal                                 to the control apparatus indicating that                                      the imaging unit is about to collide with                                     another object.                                                80   50 0L0L 0000                                                                            Operator in manual mode must exit the                                         tire in the machine because tire not in                                       position to resume auto mode.                                  81   51 0L0L 000L                                                                            X-ray carriage 620 is operating too                                           slowly, or in wrong direction, as indi-                                       cated by the potentiometer 620P.                               82   52 0L0L 00L0                                                                            The potentiometer 620P produces a signal                                      to the control apparatus indicating that                                      the X-ray carriage has moved beyond its                                       computer controlled travel limit.                              83   53 0L0L 00LL                                                                            Spindle insert/remove drive 510M is                                           operating in wrong direction, or too                                          slowly, as detected by the signal from the                                    potentiometer 510P.                                            84   54 0L0L 0L00                                                                            The potentiometer 510P produces a signal                                      to the control apparatus indicating that                                      the spindle carriages have moved beyond                                       their computer control travel limit.                           85   55 0L0L 0L0L                                                                            The image system subcarriage 390 is                                           operating too slowly or in the wrong                                          direction, as sensed by the potentiometer                                     390P.                                                          86   56 0L0L 0LL0                                                                            The potentiometer 390P produces a signal                                      to the control apparatus indicating that                                      the imaging system subcarriage has                                            traveled beyond its computer controlled                                       permitted travel limit.                                        87   57 0L0L 0LLL                                                                            Imaging system sub-subcarriage 420 is                                         operating too slowly or in the wrong                                          direction, as sensed by the potentiometer                                     420P.                                                          88   58 0L0L L000                                                                            The potentiometer 420P produces a signal                                      to the control apparatus indicating that                                      the imaging system sub-subcarriage has                                        moved beyond its computer controlled per-                                     mitted travel limit.                                           89   59 OLOL L00L                                                                            Tire centering drive 161M is operating                                        too slowly or in the wrong direction, as                                      sensed by the potentiometer 161P.                              90   5A 0L0L L0L0                                                                            The potentiometer 161P produces a signal                                      to the control apparatus indicating that                                      the drive of the arm assemblies 161 is                                        beyond its computer controlled permitted                                      travel limit.                                                  91   5B 0L0L L0LL                                                                            The centering table drive 140M is                                             operating too slowly, or in the wrong                                         direction, as sensed by the potentiometer                                     140P.                                                          92   5C 0L0L LL00                                                                            The potentiometer 140P produces a signal                                      to the control apparatus indicating that                                      the centering table 120 has been raised                                       or lowered beyond its computer controlled                                     permitted travel limit.                                        93   5D 0L0L LL0L                                                                            Main conveyor gear rack drive 460M is                                         operating too slowly, or in the wrong                                         direction, as sensed by the potentiometer                                     460P.                                                          94   5E 0L0L LLL0                                                                            The potentiometer 460P produces a signal                                      to the control apparatus indicating that                                      the gear racks 460 of the main conveyor                                       have been raised or lowered beyond their                                      computer controlled travel limit.                              95   5F 0L0L LLLL                                                                            The imaging system carriage drive 340M                                        is operating too slowly, or in the                                            wrong direction, as sensed by the poten-                                      tiometer 340P.                                                 96   60 0LL0 0000                                                                            The potentiometer 340P produces a signal                                      to the control apparatus indicating that                                      the imaging system carriage 340 has moved                                     outside its computer controlled travel                                        limit.                                                         97   61 0LL0 000L                                                                            X-ray tube pivoting drive 700M is                                             operating too slowly or in the wrong                                          direction as sensed by the potentiometer                                      700P.                                                          98   62 0LL0 00L0                                                                            The potentiometer 700P produces a signal                                      to the control apparatus indicating that                                      the X-ray tube housing assembly has                                           pivoted beyond its permitted computer                                         controlled limits of rotation.                                 99   63 0LL0 00LL                                                                            The positioning drive                                                         820M is operating too slowly or in the                                        wrong direction, as sensed by the poten-                                      tiometer 820P.                                                 100  64 0LL0 0L00                                                                            The potentiometer 820P produces a signal                                      to the control apparatus indicating that                                      the positioning switch assembly 820 has                                       moved beyond its computer controlled per-                                     mitted travel limit.                                           101  65 0LL0 0L0L                                                                            The potentiometer 195P produces a signal                                      to the control apparatus indicating that                                      the height sensor bar 210 has moved beyond                                    its computer controlled permitted travel                                      limit.                                                         102  66 0LL0 0LL0                                                                            The potentiometer 510P produces a signal                                      to the control apparatus indicating that                                      the spindles are inserted or removed be-                                      yond their computer controlled permitted                                      travel limit.                                                  103  67 0LL0 0LLL                                                                            The control apparatus detects the occur-                                      rence of a malfunction in the digital to                                      analog converter 1336, requiring service.                      104  68 0LL0 L000                                                                            The control apparatus, through a connec-                                      tion thereto, detects a malfunction                                           in the analog to digital converter 1332,                                      requiring service.                                             105  69 0LL0 L00L                                                                            The measurements of tire outside diameter                                     and width indicate that the apparatus 100                                     would have to drive one of its components                                     past its limited path to handle the tire.                      __________________________________________________________________________

Although the invention has been described in its preferred form with acertain degree of particularity, it is understood that the presentdisclosure of the preferred form has been made only by way of exampleand numerous changes in the details of construction and the combinationand arrangement of parts may be resorted to without departing from thespirit and the scope of the invention as hereinafter claimed.

What is claimed is:
 1. In an apparatus for inspecting tires, of the typeincluding:a. a structure defining an inspection station; b. apositioning unit positioned upstream from the inspection station forsequentially receiving tires to be inspected from a source of tires, forpositioning each tire laterally of a feed path, and for feedingpositioned tires one at a time along the feed path toward the inspectionstation; c. the positioning unit including a pair of arms one of whichis positioned on each side of the feed path, the unit also including areversible drive system interconnecting the arms for relative movementto engage and position a tire interposed between said arms in directionslaterally of said feed path; d. the improvement whereby each of saidarms carries a separate sensor assembly, each of which sensor assembliescomprises:i. a member movably carried by its arm at a position betweensaid arms for engaging such tire when said arms move toward each other,said member being movable relatively to its arm; ii. biasing meansbiasing said member toward the other; and, iii. an electrical sensoroperably connected to said member and its arm to sense relative movementbetween said member and its arm for providing an electrical signalvariation when said member is moved relative to its arm in response toengagement of said member with such tire.
 2. The apparatus of claim 1wherein each of said arms are carried on a separate support, each ofsaid supports engages a separate threaded region along a threaded rodextending beside said arms, one of said separate regions having R.H.threads, the other of said regions having L.H. threads, and said rod isoperably connected to said drive system such that when said rod isrotated in one direction, said arms are caused to move concurrentlytoward each other, and when said rod is rotated in the oppositedirection, said arms are caused to move concurrently away from eachother.
 3. In an apparatus for inspecting tires, of the type including:a.a structure defining an inspection station; b. a width sensing unitpositioned upstream from the inspection station for sequentiallyreceiving tires to be inspected from a source of tires and for sensingthe width of each tire, said sensing unit including an arm movable intoengagement with one side of a tire; c. the improvement whereby said armcarries a sensor assembly which comprises:i. a member movably carried bysaid arm at a position between said arm and such tire for engaging suchtire when said arm moves toward said tire; ii. biasing means biasingsaid member in a direction toward such tire; and iii. an electricalsensor operably connected to said member and said arm to sense relativemovement between said member and said arm for providing an electricalsignal variation when said member is moved relative to said arm inresponse to engagement of said member with such tire.
 4. The apparatusof claim 3 wherein said arm is supported on at least one gear rack formovement toward and away from such tire, and a reversible drive systemis provided for moving said gear rack in directions toward and away fromsuch tire.
 5. The apparatus of claim 4 wherein said drive systemincludes a fluid motor arranged to move a piston when pressurized air issupplied to said motor, and drive means interconnecting said piston withsaid gear rack for moving said gear rack in response to movement of saidpiston.
 6. The apparatus of claim 4 wherein said drive means includes:a.a cable having end portions connected to said piston for movementtherewith and having an intermediate portion reeved around a pair ofspaced pulleys with a reach extending between said pulleys; b. a rollerchain reeved around a pair of spaced sprockets having a reach whichparallels said cable reach, one of said sprockets being drivinglyconnected to said gear rack; and c. connection means forming aconnection between said reaches whereby, when said piston moves, saidcable causes said roller chain to turn said one sprocket which, in turn,moves said gear rack.
 7. In an apparatus for inspecting tires, of thetype including:a. a structure defining an inspection station; b. aconveyor positioned upstream from said inspection station forsequentially receiving tires to be inspected from a source of tires, forsupporting said tires for movement along a feed path with one sidewallof a supported tire in engagement with said conveyor; c. a tire widthsensor carried by said conveyor for engaging the opposite sidewall ofsuch tire and providing an indication of sensed tire width; d. theimprovement of a drive system for moving portions of said conveyor toposition such tire with its center plane substantially coincident with apredetermined inspection plane when such tire enters said inspectionstation, the drive system comprising:i. at least one gear rack connectedto said conveyor portions; ii. a rotatable shaft carrying a gear inmeshing engagement with said gear rack; iii. a reversible drive motoroperably connected to said shaft to rotate said gear and thereby movesaid gear rack to move said conveyor portions.
 8. In an apparatus forinspecting tires, the improvement of a system for supporting tires oneat a time at an inspection station, comprising:a. a main frame havingfour upstanding columns; b. four threaded rods extending in parallelrelationship along separate ones of said columns and being supported bybearings carried on said columns, each of said threaded rods having anupper end region and a lower end region, one of said end regions beingprovided with L.H. threads and the other end region being provided withR.H. threads; c. a pair of tire engaging assemblies, one of saidassemblies being supported on said upper end regions of said rods, theother of said assemblies being supported on the lower end regions ofsaid rods; and d. a first reversible drive means operably connected tosaid rods to concurrently rotate said rods to concurrently move saidassemblies toward and away from each other.
 9. The apparatus of claim 8wherein:a. each of said assemblies includes a carriage and at least onespindle rotatably carried by said carriage for engaging portions of atire positioned between said assemblies; b. a splined drive shaft issupported by said main frame with its axis paralleling the axes of saidrods; c. connecting means are provided on each of said carriages todrivingly engage said splined shaft regardless of the position of saidcarriages and to provide a driving connection between said splined shaftand said rotatable spindles; and d. a second drive means is operablyconnected to said splined shaft to concurrently rotate said spindles.10. The apparatus of claim 9 wherein:a. each of said carriage carries atotal of four of said spindles; and b. each of said connecting meansinclude sprockets connected to said spindles and to said splined shaft,and roller chain means drivingly connecting said sprockets to rotatesaid spindles in response to rotation of said splined shaft.
 11. Theapparatus of claim 9 additionally including sensor means connected tosaid splined shaft for providing a variation in an electrical signalindicative of the speed of rotation of said spindles.
 12. In anapparatus for inspecting tires, the improvement of a system forsupporting tires one at a time at an inspection station, comprising:a. asupport structure defining an inspection station; b. first and secondsets of spindles positioned on opposite sides of a tire positioned insaid inspection station; c. the spindles of each set being arranged inpairs and being supported near one end region of separate arms; d. saidarms having portions pivotally connected to said support structure; ande. the arms supporting each pair of spindles having reaches intermediatesaid portions and said end regions, said reaches being criss-crossed inscissors fashion.
 13. The apparatus of claim 12 wherein:a. said arms areeach of a generally L-shaped configuration having two legs extending indifferent directions from its axis of pivotal connection with saidsupport structure; b. one of said legs carries one of said spindles; c.the other of said legs being connected to a drive means for pivotingsaid arm about said axis.
 14. The apparatus of claim 13 wherein saidother legs of the arms supporting each pair of spindles are connected ata common place with said drive means.
 15. In an apparatus for inspectingtires, the improvement of a system for supporting tires one at a time atan inspection station, comprising:a. a support structure defining aninspection station; b. a pair of movable carriages positioned onopposite sides of a tire positioned in said inspection station; c. drivemeans for moving said carriages concurrently toward and away from suchtire; d. four spindles carried on each of said carriages, said spindlesbeing arranged in pairs and being carried on pairs of criss-crossed armspivotally mounted on said carriages for insertion into such tire in aretracted position and for extension into engagement with the beads ofsuch tire to support such tire.
 16. The apparatus of claim 15 wherein:a.each of said arms is pivotally carried on a separate shaft journaled inone of said carriages; b. each of said shafts carries a first sprocket;c. each of said spindles is rotatably mounted on its respective arm andcarries a second sprocket; and d. a drive chain is reeved around saidfirst and second sprockets to rotate said spindles in response torotation of said shafts.
 17. The apparatus of claim 16 including drivemeans interconnecting said shafts for concurrent rotation.
 18. Theapparatus of claim 15 additionally including regulating means forregulating the force which said spindles apply to such tire in engagingthe beads of such tire.
 19. The apparatus of claim 18 wherein apneumatic drive system is connected with said arms for concurrentlyexpanding said arms, and said regulating means includes a pressureregulator for regulating the pressure of compressed air supplied to saiddrive system.
 20. In an apparatus for inspecting a tire at an inspectionstation while such tire is supported by spindles which engage the beadsof such tire, the improvement of means for selectively controlling theforce imposed by said spindles on the tire beads.
 21. The apparatus ofclaim 20 wherein:a. said spindles include a plurality of spindlesmovable inwardly away from and outwardly toward said tire beads; b. afluid operated drive system is provided for moving said spindlesinwardly and outwardly; and c. said force control means includespressure regulation means for regulating the pressure of fluid suppliedto said drive system.
 22. A method of inspecting tires, comprising thesteps of:a. feeding tires to be inspected one at a time to an inspectionstation; b. sensing the outer diameter of each tire; c. supporting eachtire at said inspection station on a plurality of spindles which engageopposite sides of each of the beads of such tire; d. selecting the forceto be applied by said spindles to such tire beads as a function of theouter diameter of such tire, larger forces being used with larger tiresand smaller forces being used with smaller tires; and e. inspecting theintegrity of each tire as it is supported on said spindles.
 23. A methodof inspecting tires, comprising the steps of:a. feeding tires to beinspected one at a time to an inspection station; b. moving a pluralityof spindles axially into such tire; c. after said spindles arepositioned inwardly of such tire, pivoting said spindles oncriss-crossed arms to move said spindles into engagement with the beadsof such tire to support such tire for inspection; and d. inspecting suchtire while it is supported by said spindles.
 24. The method of claim 23additionally including the step of regulating the force applied by saidspindles to such tire beads in accordance with tire size, larger forcesbeing applied to larger tires and smaller forces being applied tosmaller tires.
 25. The method of claim 23 additionally including thestep of rotating said spindles concurrently after said spindles aresupporting such tire to rotate such tire.
 26. The method of claim 23additionally including the step of moving said spindles to axiallyspread the beads of such tire after said spindles are supporting suchtire.
 27. An apparatus for inspecting tires, comprising:a. a support; b.inspection structure carried on said support and defining an inspectionstation, including:i. at least one pair of spindles; ii. a pair ofcrossed arm members pivotally supported on said structure and eachcarrying a separate one of said spindles; c. a positioning unit carriedon said support and being positioned upstream from said inspectionstation for sequentially receiving tires to be inspected from a sourceof tires, for positioning each tire laterally of a feed path, and forfeeding positioned tires one at a time along the feed path toward theinspection station; d. the positioning unit including a pair of arms oneof which is positioned on each side of the feed path, the unit alsoincluding a reversible drive system interconnecting the arms forrelative movement to engage and position a tire interposed between saidarms in directions laterally of said feed path; e. the improvementwhereby each of said arms carries a separate sensor assembly, each ofwhich sensor assemblies comprises:i. a member movably carried by its armat a position between said arms for engaging such tire when said armsmove toward each other, said member being movable relatively to its arm;ii. biasing means biasing said member toward the other; and iii. anelectrical sensor operably connected to said member and its arm to senserelative movement between said member and its arm for providing anelectrical signal variation when said member is moved relative to itsarm in response to engagement of said member with such tire.
 28. Anapparatus for inspecting tires, comprising:a. a support; b. inspectionstructure carried on said support and defining an inspection station,including:i. at least one pair of spindles; ii. a pair of crossed armmembers pivotally supported on said structure and each carrying aseparate one of said spindles; c. a width sensing unit carried on saidsupport and positioned upstream from the inspection station forsequentially receiving tires to be inspected from a source of tires andfor sensing the width of each tire, said sensing unit including a sensorarm movable into engagement with one side of a tire; and, d. sensormeans carried on said sensor arm, including;i. a member movably carriedby said sensor assembly arm at a position between said sensor arm andsuch tire for engaging such tire when said sensor arm moves toward saidtire; ii. biasing means biasing said member in a direction toward suchtire; and iii. an electrical sensor operably connected to said memberand said sensor arm to sense relative movement between said member andsaid sensor arm for providing an electrical signal variation when saidmember is moved relative to said sensor arm in response to engagement ofsaid member with such tire.
 29. In an apparatus for inspecting tires,the improvement of a system for supporting tires one at a time at aninspection station, comprising:a. a support structure defining aninspection station; b. at least one pair of spindles; c. a pair ofcrossed arms each having one end region pivotally connected to saidstructure and each having an opposite end region which carries aseparate one of said spindles; and d. said arms each having anintermediate reach between its end regions, said reaches beingcriss-crossed in scissors fashion.